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【324218】2024八年级数学下册 专题6.1 反比例函数中的综合(压轴题专项讲练)(含解析)(新

时间:2025-01-15 21:42:42 作者: 字数:32132字
简介:


 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 专题6.1 反比例函数中的综合


 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【典例1如图1,已知点Aa0),B0b),且ab满足 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 0,平行四边形ABCD的边ADy轴交于点E,且EAD中点,双曲线y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 经过CD两点.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

1a的值为  b的值为  

2)求k的值;

3)点P在双曲线POQ上,点Qy轴上,若以点ABPQ为顶边的四边形是平行四边形,直接写出满足要求的所有点PQ的坐标.

Shape1 思路点拨】

1)先根据非负数的性质求出ab的值;

2)故可得出AB两点的坐标,设D1t),由DCAB,可知C2t﹣2),再根据反比例函数的性质求出t的值即可;

3)由(2)知k4可知反比例函数的解析式为y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,再由点P在双曲线y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 上,点Qy轴上,设Q0y),Px <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),再分以AB为边和以AB为对角线两种情况求出x的值,故可得出PQ的坐标.

Shape2 解题过程】

解:(1)∵ab满足 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 0

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

故答案是:﹣1;﹣2

2)∴A(﹣10),B0,﹣2),

EAD中点,

xD1

D1t),

又∵四边形ABCD是平行四边形,

C2t﹣2).

t2t﹣4

t4

D14),

D14)在双曲线y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 上,

kxy1×44

3)∵点P在双曲线y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 上,点Qy轴上,

Q0y),Px <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

AB为边时:如图1所示:

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

ABPQ为平行四边形,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 0,解得x1,此时P114),Q106);

如图2所示:

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

ABQP为平行四边形,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x,解得x=﹣1,此时P2(﹣1,﹣4),Q20,﹣6);

如图3所示:

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

AB为对角线时:APBQ,且APBQ

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,解得x=﹣1

P3(﹣1,﹣4),Q302);

综上所述,P114),Q106);P2(﹣1,﹣4),Q20,﹣6);P3(﹣1,﹣4),Q302).


 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

1.(前进区一模)如图,过y轴上任意一点Px轴的平行线,分别与反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象交于A点和B点,若Cx轴上任意一点,连接ACBC,则△ABC的面积为(  )

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

A3 B4 C5 D8

【思路点拨】

连接AOBO,得到△ABC的面积和△ABO的面积相等,然后借助反比例函数的几何意义求得△AOP和△BOP的面积,最后得到△ABC的面积.

【解题过程】

解:连接AOBO

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

ABx轴,

SABCSABO

A点和B点分别在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象上,

SAOP <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 1SBOP <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 3

SABCSAOP+SBOP1+34

SABO4

故选:B

2.(宁波模拟)如图△OAB,△BCD的顶点AC在函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k0x0)的图象上,点BDx轴正半轴上,AOABCBCDBD2OB,设△AOB,△CBD的面积分别为S1S2,若S1+S24,则k的值为(  )

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

A2 B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> D3

【思路点拨】

过点AAMx轴于点M,过点CCNx轴于点N,由AOABCBCDBD2OB,得OMBMBNDN,设OMaAMb,则点Aab),点C4aCN),再由反比例系数k的几何意义得到S1S2的表达式,最后由S1+S24求得k的取值.

【解题过程】

解:如图,过点AAMx轴于点M,过点CCNx轴于点N

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

AOABCBCDBD2OB

OMBMBNDN

OMaAMb,则点Aab),点C4aCN),

AC在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k0x0)的图象上,

ab4aCNk,即CN <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> b

S1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> S2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

S1+S24

k <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k4

k <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

故选:C

3.(费县一模)如图,点AB在反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象上,ACx轴于点CBDx轴于点DBEy轴于点E,连结AE.若OE23OC2ODACAE,则k的值为(  )

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

A8 B9 C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> D <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

根据题意求得B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k1),进而求得A <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k3),然后根据勾股定理得到32=( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k2+12,解方程即可求得k的值.

【解题过程】

解:∵BDx轴于点DBEy轴于点E

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

四边形BDOE是矩形,

BDOE2

y2代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,求得x <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k

B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k2),

OD <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k

3OC2OD

OC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k

ACx轴于点C

x <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 得,y3

AEAC3

OCEF <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> kAF3﹣21

Rt△AEF中,AE2EF2+AF2

32=( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k2+12,解得k±6 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

在第一象限,

k6 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

故选:C

4.(姑苏区校级期中)如图,点B为反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k0x0)上的一点,点A2k0)为x轴负半轴上一点,连接AB,将线段AB绕点A逆时针旋转90°;点B的对应点为点C.若点C恰好也在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象上,且C点的横坐标是A点横坐标的两倍,则k=(  )

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

A <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> D <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

先判断出△ABF≌△CAEAAS),得出AFCEBFAE,再判断出点C的横坐标,进而得出点C的纵坐标,再利用BFAE,求出点B的纵坐标,进而得出点B的横坐标,最用AFCE,建立方程求解即可得出结论.

【解题过程】

解:如图,过点CCEx轴于E,过点BBFx轴于F

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

∴∠AEC=∠BFA90°

∴∠BAF+∠ABF90°

由旋转知,ABAC,∠BAC90°

∴∠CAE+∠BAF90°

∴∠ABF=∠CAE

∴△ABF≌△CAEAAS),

AFCEBFAE

C点的横坐标是A点横坐标的两倍,且点A2k0),

E4k0),

C在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象上,

C4k <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

CE <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

A2k0),E4k0),

AE2k﹣4k=﹣2k

BF=﹣2k

B在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象上,

B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,﹣2k),

F <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 0),

AF <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2k

AFCE

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2k <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

k <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

故选:D

5.(十堰月考)如图,在直角坐标系xOy中,点AB分别在x轴和y轴上, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> .∠AOB的角平分线与OA的垂直平分线交于点C,与AB交于点D,反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象过点C.当△ACD面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 时,k的值是(  )

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

A <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> B4 C7 D8

【思路点拨】

OA3m,先求出直线AB的解析式,进一步求出DC点坐标,再用两点之间的距离公式求出OCDC的长,根据△ACD的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,得出△AOC的面积,根据反比例函数k的几何意义即可求出k的值.

【解题过程】

解:设OA3m

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

OB4m

A3m0),B04m),

AB解析式:ykx+b

代入AB点坐标,

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

解得k <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> b4m

AB解析式:y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x+4m

OD平分∠AOB

OD的解析式:yx

联立y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x+4myx

x <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> m

D <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> m),

OA的垂直平分线交OA于点M,连接AC

M <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 0),

C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

OC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> CD <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

OC7CD

SAOC7SACD <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

k <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

故选:A

6.(虎丘区校级模拟)如图,反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象经过点A21),过AABy轴于点B,连OA,直线CDOA,交x轴于点C,交y轴于点D,若点B关于直线CD的对称点B恰好落在该反比例函数图象上,则B点纵坐标为(  )

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

A <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> D <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

利用待定系数法求得反比例函数的解析式,由点A的坐标可得AB2OB1;设BB交直线CD于点E,过点EEGBDG,过BBFBD于点F,利用待定系数法求得直线OABB的解析式和反比例函数的解析式,进而求得点B的坐标,则点B的纵坐标可求.

【解题过程】

解:设BB交直线CD于点E,过点EEGBDG,过BBFBD于点F,如图,

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

BB关于直线CD对称,

CD垂直平分BB

EBB的中点,EBEB

EGBDBFBD

EGBF

EG <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> BF

直线OA经过点A21),

直线OA的解析式为:y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x

CDOABB′⊥CD

BB′∥OA

设直线BB的解析式为y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x+b

B01),

b1

直线BB的解析式为y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x+1

反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象经过点A21),

反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

联立方程得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ).

故选:A

7.(鹿城区校级二模)如图,点A是反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k0)在第一象限内图象上的点,ABy轴于点Bx轴正半轴上有一点CABACk,连结OABC相交于D,若SCODSABD1,则k的值为  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

根据题目的条件求出A点的纵坐标,再求得△OBC的面积,根据△OBC与△OAB的面积关系列出k的方程解答便可.

【解题过程】

解:∵ABACkABy轴于点B

A点横坐标为k

xk时,y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

Ak1),

A点作AEx轴于点E,则OBAE1OEABk

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

CE <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

SCODSABD1

SOBCSOAB1

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

解得k <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> (舍)或k <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

8.(潍城区一模)如图,在平面直角坐标系中,点B的坐标为(﹣40),ABx轴,反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象与AB交于点C,与OA交于点E,且AC4BCSAOC20,则点E的坐标为 ( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ) 

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

根据点B的坐标为(﹣40)得出OB4,由ABx轴,SAOC20求出AC长度,根据AC4BC得到点C、点A的坐标,利用待定系数法求出反比例函数以及直线AO的解析式,然后联立两解析式即可求解.

【解题过程】

解:∵B(﹣40),ABOB

A横坐标为﹣4OB4

SAOC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> OBAC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 4•AC20

AC10

AC4BC

BC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> AC2.5

C坐标为(﹣42.5),ABAC+BC12.5,点A坐标为(﹣412.5),

k=﹣4×2.5=﹣10

y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

设直线OA解析式为ymx

A(﹣412.5)代入ymx

得﹣4m12.5,解得m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x

解方程组 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,或 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> (不合题意舍去),

E坐标为( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ).

故答案为:( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ).

9.(姑苏区模拟)如图,平行四边形OABC的顶点Ax轴的正半轴上,点D43)在对角线OB上,反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象经过CD两点.已知平行四边形OABC的面积是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,则点B的坐标为 (5 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ) 

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

利用点D坐标求出反比例函数和正比例函数解析式,再设出点C坐标,利用平行四边形的性质和正比例函数解析式表示出点B的坐标,从而可得BC,再用BC与点C的纵坐标表示出平行四边形的面积,求解即可.

【解题过程】

解:∵点D43)在对角线OB上,

OB的解析式为:y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x

反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象经过CD两点,

k12

反比例函数的解析式为:y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

C在反比例函数图象上,

设点C坐标为(a <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

四边形OABC为平行四边形,

BCOA

B的纵坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 代入y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x

解得:x <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

B坐标为( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

BC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> a

平行四边形OABC的面积是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> a <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

解得:a <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> a <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> (舍去),

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 5 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

B坐标为:(5 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

故答案为:(5 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ).

10.(徐汇区二模)如图,已知点A08)和点B48),点B在函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象上,点CAB的延长线上一点,过点C的直线交x轴正半轴于点E、交双曲线于点D.如果CDDE,那么线段CE长度的取值范围是 8≤CE8 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

由题意可得ABx轴,利用待定系数法确定出反比例函数的解析式,过点DDFOA于点F,则得DFAB,利用梯形的中位线定理可得AFOF <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 4,则点D纵坐标可得,利用反比例函数解析式可求点D坐标;分两种情况得到线段CE的极值:当ECx轴时,EC最小;当点E与点O重合时EC最大,利用点D坐标即可求得两种情况下的EC的值,结合已知条件即可得出结论.

【解题过程】

解:∵A08),B48),

ABx轴.

B在双曲线y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)上,

8 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

k32

过点DDFOA于点F,如图,

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

DFAB

A08),

OA8

CDDE

AFOF <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> OA4

D的纵坐标为4

D在双曲线y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 上,

x8

D84).

ECx轴时,此时EC最小,ECOA8

当点E与点O重合时,此时EC最大,

CDDE

C168),

EC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 8 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

Ex轴正半轴,

8≤CE8 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

故答案为:8≤CE8 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

11.(咸丰县模拟)如图,平面直角坐标系xOy中,函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象上AB两点的坐标分别为Ann+1),Bn﹣5,﹣2n).

1)求反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 和直线AB的解析式;

2)连接AOBO,求△AOB的面积.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)根据反比例函数系数kxy得出nn+1)=(n﹣5)(﹣2n),即n2+n=﹣2n2+10n3n2﹣9n0,解方程求得AB的坐标,进而即可利用待定系数法求得函数的解析式;

2)求得D的坐标,然后利用三角形面积公式即可求得.

【解题过程】

解:(1)∵AB两点在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象上,而Ann+1),Bn﹣5,﹣2n),

nn+1)=(n﹣5)(﹣2n),即n2+n=﹣2n2+10n3n2﹣9n0

解得n10n23

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象与坐标轴没有交点,

n10舍去,

n3

A34),B(﹣2,﹣6),

k3×412

设直线AB的解析式为:yax+b

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

直线AB的解析式为:y2x﹣2,反比例函数解析式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

2)设直线ABx轴于点D,则

y0时,2x﹣20

x1

D10),

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

∴△AOB的面积为5

12.(市中区一模)已知正方形OABC的面积为9,点O是坐标原点,点Ax轴上,点Cy轴上,点B在函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0k0)的图象上,点Pmn)是函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0k0)的图象上任意一点.过点P分别作x轴、y轴的垂线,垂足分别为EF.若矩形OEPF和正方形OABC不重合部分(阴影)面积为S.(提示:考虑点P在点B的左侧或右侧两种情况)

1)求B点的坐标和k的值;

2)写出S关于m的函数关系式;

3)当S3时,求点P的坐标.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)由正方形的性质可求B点坐标,再将B点代入函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,即可求k

2)分两种情况求:当点P在点B的左侧时,即0m3时,S33﹣m)=9﹣3m;当点P在点B的右侧时,即m3时,S9 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

3)将S3代入(2)中所求表达式,即可求m的值.

【解题过程】

解:(1)∵正方形OABC的面积为9

OAOC

B33),

B点在函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0k0)的图象上,

k9

2)当点P在点B的左侧时,即0m3时,

Pmn)是函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 图象上的点,

mn9

A30),C03),

S33﹣m)=9﹣3m

当点P在点B的右侧时,即m3时,

S=(m﹣3n9﹣3n

n <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

S9 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

3)当点P在点B的左侧时,S9﹣3m3

m2

P2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> );

当点P在点B的右侧时,S9 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 3

m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

P <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2);

综上所述:P点坐标为(2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> )或( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2).

13.(信阳模拟)如图,直线y=﹣2x+bx轴、y轴分别相交于点AB,以线段AB为边在第一象限作正方形ABCD,已知AB2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

1)求直线AB的解析式;

2)求点D的坐标,并判断点D是否在双曲线y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 上,说明理由.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)根据点AB的坐标,利用待定系数法可求出直线AB的解析式;

2)作DFx轴于F,易证△ADF≌△BAOAAS),利用全等三角形的性质可求出点D的坐标,利用kxy即可判断.

【解题过程】

解:(1)∵直线y=﹣2x+bx轴、y轴分别相交于点AB

A <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 0),B0b),

OA <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> OBb

AB2OA2+OB2

2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2=( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2+b2,解得b4(负数舍去),

直线AB的解析式为y=﹣2x+4

2)由(1)可知OA2OB4

DFx轴于F,则∠AFD90°

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

正方形ABCD

BAAD,∠BAD90°,∠BAO+∠DAF90°

∵∠BAO+∠ABO90°

∴∠ABO=∠DAF

在△ADF和△BAO中,

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

∴△ADF≌△BAOAAS),

AFBO4DFAO2

D的坐标为(62),

6×212

D在双曲线y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 上.

14.(吉林二模)如图,点P32)在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象上,过点PPMx轴交反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象于点M,作PNy轴交反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象于点N,连接MN

1)求k的值;

2)求△PMN的面积;

3)连接OMON,直接写出△MON的面积.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)将点P32)代入反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 可求出k的值;

2)根据点P32)在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,可得出OAPN2OBPA3,由点M、点N在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象上,求出AMBN,再求出PMPN,利用三角形面积计算公式进行计算即可;

3)根据面积之间的关系可得答案.

【解题过程】

解:(1)∵点P32)在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象上,

k3×26S矩形OAPB

答:k的值为6

2)如图,延长PMPNx轴、y轴分别为MN

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

P32

OBPA3OAPB2

M、点N在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象上,OA2OB3

AM1BN <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

PMPAAM3﹣12PNPBBN2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

SPMN <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

答:△PMN的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

3)△MON的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> .理由:

M、点N在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象上,

SOAMSBON1

SMONS矩形OAPBSOAMSBONSPMN

6﹣1﹣1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

答:△MON的面积是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

15.(姑苏区模拟)如图,已知点P在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 上,过点P分别作PAx轴,垂足为点APBy轴,垂足为点B.连接AB,将△PAB绕点A顺时针旋转90°到△QAC,交反比例函数图象于点D

1)若点P24),求SAPD

2)若CD1SAPDSADQ31,求反比例函数解析式.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)由P的坐标,根据题意即可求得APAQ4,利用三角形面积公式即可求得SAPD <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> APAQ8

2)设P的坐标为(mn),根据题意Dm+nm﹣1),根据SAPDSADQ31,即可得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> n2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> mnn),即n3m﹣1),利用反比例函数系数k的几何意义得到mn=(m+n)(m﹣1),整理得,nm2m,从而得到m2m3m﹣1),即m2﹣4m+30,求得m3,进而求得P为(36),利用待定系数法即可求得反比例函数的解析式.

【解题过程】

解:(1)由题意可知APAQ4

APCQ

SAPD <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> APAQ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 8

2)设P的坐标为(mn),

P在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 上,过点P分别作PAx轴,垂足为点APBy轴,垂足为点B

OABPmPAn

将△PAB绕点A顺时针旋转90°到△QAC

AQPAnCQBPm

CD1

DQm﹣1

Dm+nm﹣1),

SADQ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> AQDQ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> nm﹣1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

SAPDSADQ31

SAPD <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> mnn),

SAPD <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> APAQ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> nn <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> n2

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> n2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> mnn),即n3m﹣1),

反比例函数图象过PD点,

mn=(m+n)(m﹣1),整理得,nm2m

m2m3m﹣1),即m2﹣4m+30

解得m3m1

m3时,n6

m1时,n0(不合题意,舍去),

P36),

k3×618

反比例函数的解析式为y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

16.(寻乌县模拟)反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象经过矩形ABCD的顶点ACAC的垂直平分线分别交ABCD于点PQ;已知点B坐标为(12),矩形ABCD的周长为12

1)求反比例函数的解析式;

2)连接PCAQ,判断四边形APCQ的形状,并说明理由.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)由题意可知A1k),C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2),即可得出ABk﹣2BC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 1,根据矩形的周长得到关于k的方程,解方程即可求得k的值,从而求得反比例函数的解析式;

2)根据全等得出MPMQ,推出四边形是平行四边形,再根据PQAC即可推出四边形是菱形.

【解题过程】

解:(1)由题意可知A1k),C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2),

ABk﹣2BC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 1

矩形ABCD的周长为12

2AB+BC)=12,即2k﹣2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 1)=12

解得k6

反比例函数的解析式为y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

2)四边形APCQ是菱形,

理由是:设PQAC的交点为M

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

PQAC的垂直平分线,

AMMC,∠AMP=∠CMQ90°

四边形ABCD是矩形,

ADBC

∴∠PAM=∠QCM

在△APM和△CQM

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

∴△APM≌△CQMASA);

MPMQ

又∵AMCM

四边形APCQ是平行四边形,

又∵PQAC

平行四边形APCQ是菱形.

17.(信阳模拟)如图,在矩形OABC中,BC4OCOA分别在x轴、y轴上,对角线OBAC交于点E;过点EEFOB,交x轴于点F.反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象经过点E,且交BC于点D,已知SOEF5CD1

1)求OF的长;

2)求反比例函数的解析式;

3)将△OEF沿射线EB向右上方平移 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 个单位长度,得到△O'E'F',则EF的对应线段E'F'的中点 不能 (填“能”或“不能”)落在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象上.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)根据矩形的性质得出SOBF10,然后根据三角形面积即可求得OF

2根据垂直平分线的性质得出BFOF5,然后根据勾股定理求得CF,即可得出D81),利用待定系数法即可求得反比例函数的解析式;

3)求得EF平移后的中点的坐标,即可判断EF的对应线段E'F'的中点不能落在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象上.

【解题过程】

解:(1)连接BF

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

由矩形的性质可知,OEBE

SBEFSOEF5

SOBF10

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> OFBC10,即 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> OF×410

OF5

2)∵OEBEEFOB

BFOF5

FC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 3

OCOF+CF8

CD1

D81),

反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象经过点D

k8×18

反比例函数的解析式为y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

3)∵B84),

E42),

F50),

EF中点的坐标为( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 1),

将△OEF沿射线EB向右上方平移 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 个单位长度,得到△O'E'F',则EF的对应线段E'F'的中点为( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 11 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),即( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 8

EF的对应线段E'F'的中点不能落在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象上.

故答案为:不能.

18.(叙州区期中)已知反比例函数的图象经过三个点A(﹣2,﹣3),B2my1),C3my2),其中m0

1)求反比例函数的关系式;

2)当y1y22时,求m的值:

3)如图,过点BC分别作x轴、y轴的垂线,两垂线相交于点D,点Px轴上,若△PBD的面积是6,请求出点P坐标(横坐标用含m的式子表示).

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)先根据反比例函数的图象经过点A(﹣2,﹣3),利用待定系数法求出反比例函数的解析式为y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

2)由反比例函数图象上点的坐标特征得出y1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> y2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,再根据y1y22列出方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2,解方程即可求出m的值;

3)设BDx轴交于点E.根据三角形PBD的面积是6,列出方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> PE6,求出PE12m,再由E2m0),点Px轴上,即可求出点P的坐标.

【解题过程】

解:(1)设反比例函数的解析式为y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

反比例函数的图象经过点A(﹣2,﹣3),

k=﹣(﹣3)=6

反比例函数的解析式为y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

2)反比例函数的图象经过点B2my1),C3my2),

y1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> y2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

y1y22

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2

m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

经检验,m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 是原方程的解.

m的值是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

3)设BDx轴交于点E

B2m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),C3m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),过点BC分别作x轴、y轴的垂线,两垂线相交于点D

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

D2m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),BD <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

三角形PBD的面积是6

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> BDPE6

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> PE6

PE12m

E2m0),点Px轴上,

P坐标为(﹣10m0)或(14m0).

19.(龙泉驿区期中)如图,点P是反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k10x0)图象上一动点,过点Px轴、y轴的垂线,分别交x轴、y轴于AB两点,交反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k20|k2|k1)的图象于EF两点,连接OEOFEF

1)四边形PEOF的面积S1 k1k2 (用含k1k2的式子表示);

2)设P点坐标为(23).

E的坐标是( 2   <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  ),点F的坐标是(  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>   3 )(用含k2的式子表示);

若△OEF的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,求反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的解析式.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)根据反比例函数中比例系数k的几何意义即可解答;

2)①根据PEx轴,PFy轴可知,PE两点的横坐标相同,PF两点的纵坐标相同,分别把P点的横纵坐标代入反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 即可求出EF两点的坐标;

先根据P点的坐标求出k1的值,再由EF两点的坐标用k2表示出PEPF的长,再用k2表示出△PEF的面积,把(1)的结论代入求解即可.

【解题过程】

解:(1)∵点P是反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k10x0)图象上一动点,

S矩形PBOAk1

EF分别是反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k20|k2|k1)的图象上两点,

SOBFSAOE <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> |k2|

四边形PEOF的面积S1S矩形PBOA+SOBF+SAOEk1+|k2|

k20

四边形PEOF的面积S1S矩形PBOA+SOBF+SAOEk1+|k2|k1k2

故答案为:k1k2

2)①∵PEx轴,PFy轴可知,PE两点的横坐标相同,PF两点的纵坐标相同,

EF两点的坐标分别为E2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),F <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 3);

故答案为:2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 3

②∵P23)在y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k10x0)图象上,

k16

∵∴EF两点的坐标分别为E2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),F <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 3),

PE3 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> PF2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

SPEF <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 3 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> )(2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

SOEF=(k1k2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 6﹣k2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

k20

k2=﹣3

反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的解析式为y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

20.(南召县期中)已知,如图,点B坐标(24),过点B分别作BAy轴于A,作BCx轴于C,反比例函数y1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象经过AB的中点D,交BC于点E

1)求反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的解析式;

2)在y轴上找一点P,使△PDE的周长最小:

求出此时点P的坐标;

直接写出△PDE的周长的最小值为  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)根据题意求得D的坐标,然后利用待定系数法求得即可;

2)①作点D关于y轴的对称点D,连接DEy轴于P,连接PD,此时,△PDE的周长最小,求得直线DE的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

根据△PDE周长的最小值=DE+DE求得即可.

【解题过程】

解:(1)∵点B坐标(24),DAB的中点,

D点的坐标为(14),

又∵D14)在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象上,

k1×44

反比例函数的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0).

2)①作点D关于y轴的对称点D,连接DEy轴于点P,连接PD

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

此时△PDE的周长最小,

D的坐标为(14),

D的坐标为(﹣14).

E点在反比例函数上,当x2时,y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2

E点的坐标为(22),

设直线DE的解析式为yax+ba≠0).

直线yax+ba≠0)经过D(﹣14),E22),

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

直线D'E的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

x0,得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

P的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

②△PDE周长的最小值=DE+DE <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

21.(浦东新区校级期末)如图,Px轴正半轴上一点,过点Px轴的垂线,交函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象于点A,交函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象于点B,过点Bx轴的平行线,交y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 于点C,连结AC

1)当点P的坐标为(20)时,求△ABC的面积.

2)当点P的坐标为(t0)时,求△ABC的面积.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)根据已知可知点P,点A,点B的横坐标相等,点B和点C的纵坐标相等求出这些点的坐标,从而求出ABBC的长,然后求面积;

2)仿照第(1)的思路用含t的式子,表示出ABBC的长,即可解答.

【解题过程】

解:(1)∵P20),BPx轴,

xPxAxB2

x2代入y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 中得:y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

A2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

x2代入y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 中得:y2

B22),

AB <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

BCx轴,

yCyB

y2代入y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 中得:2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

解得:x <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2),

BC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

∴△ABC的面积 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

答:△ABC的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

2)∵Pt0),BPx轴,

xPxAxBt

xt代入y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 中得:y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

At <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

xt代入y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 中得:y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

Bt <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

AB <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

BCx轴,

yCyB

y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 代入y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 中得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

解得:x <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

BC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

∴△ABC的面积 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

答:△ABC的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

22.(蓬江区校级二模)如图①,已知点A(﹣20),B0,﹣4),平行四边形ABCDADy轴交于点E,且EAD的中点,反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象经过CD两点.

1)求反比例函数解析式;

2)如图②,延长DC,交x轴于点F,连接OC,在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象是否存在点P,使得SPCESOCE?若存在,请求出点P的坐标;如果不存在,请说明理由.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)如图1,过点DDFy轴于点F,由△FDE≌△OAEASA),FDOA,设D2b),则C4b﹣4),根据反比例函数系数kxy得到2b4b﹣4),解得b8,即可得到D28),C44),进而求得反比例函数为y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

2)求得直线AD的解析式,求得E的坐标,证得CEx轴,根据题意即可得出点P与点D重合,即可解决问题.

【解题过程】

解:(1)如图1,过点DDFy轴于点F

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

EAD的中点,

AEDE

又∵DFy轴,∠AOE90°

∴∠DFE=∠AEO

在△FDE与△OAE中,

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

∴△FDE≌△OAEASA),

FDOA

A(﹣20),B0,﹣4),

FDOA2OB4

D2b),则C4b﹣4),

反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象经过CD两点,

2b4b﹣4),解得b8

D28),C44),

k2×816

反比例函数为y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

2)存在,

设直线AD的解析式为yax+b

A(﹣20),D28),

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

直线ADy2x+4

x0,则y4

E04),

C44),

CEx轴,CE4

SPCESOCE

P到直线CE的距离为4

P与点D重合,

P点的坐标为(28).

23.(金华模拟)如图,过反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k0x0)图象上的点P作两坐标轴的垂线,垂足分别为AB,与反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 相交于点EF

1)若PE3AE,求k的值;

2)当k6时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 是否是定值,若是,求出该定值;若不是,请说明理由.

3)试用k的代数式表示△PEF面积.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【思路点拨】

1)设AE的长为m,则PE的长为3m,由点E在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象上,可求出点E的坐标,进而可求出点P的坐标,根据k的几何意义解求k的值;

2)当k6时,同样设AE的长为m,可表达点E的坐标,进而可以表达点P的坐标,进而可求出PE的长,即可求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的值;

3)设AE的长为m,则可表示点EPF的坐标,进而可求出PEPF的长,进而可表达△PEF的面积.

【解题过程】

解:(1)设AEm,则PE3AE3m

PAAE+PE4m

E在反比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象上,

Em <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

OAPB <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

P4m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

P在比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k0x0)图象上,

k4m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 4

2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的值为定值5,理由如下:

AEm

Em <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

OAPB <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

P在比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)图象上,

P6m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

PA6m

PEPAAE5m

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 5

3)由(2)知,可设点E的坐标为(m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

OAPB <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

P在比例函数y <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k0x0)图象上,

Pkm <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

PAkm

PE=(k﹣1m

PBx轴与点B

Fkm <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ),

PFPBFB <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

SPEF <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> PEPF <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k﹣1m <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/279/" title="综合" class="c1" target="_blank">综合</a> <a href="/tags/282/" title="专题" class="c1" target="_blank">专题</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>


1