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【323411】2023九年级数学上册 第1章 反比例函数单元检测(新版)湘教版

时间:2025-01-16 18:32:35 作者: 字数:11221字
简介:


《反比例函数》单元检测

 

一.选择题(共10小题)

1.已知函数y=m+2 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 是反比例函数,且图象在第二、四象限内,则m的值是(  )

A3 B.﹣3 C±3 D.﹣ <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

2.已知yx成反比例函数,且x=2时,y=3,则该函数表达式是(  )

Ay=6x By= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> Cy= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> Dy= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

3.函数y=ax﹣ay= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> a0)在同一直角坐标系中的图象可能是(  )

A <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

4.若函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象在其所在的每一象限内,函数值y随自变量x的增大而减小,则m的取值范围是(  )

Am<﹣3 Bm0 Cm>﹣3 Dm0

5.如图,点A是反比例函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0)的图象上任意一点,ABx轴交反比例函数

y=﹣ <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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,以AB为边作平行四边形ABCD,其中CDx轴上,

S平行四边形ABCD为(  )

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

A2 B3 C4 D5

6.(2016•天津)若点A(﹣5y1),B(﹣3y2),C2y3)在反比例函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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,则y1y2y3的大小关系是(  )

Ay1y3y2 By1y2y3 Cy3y2y1 Dy2y1y3

7.(2016•株洲)已知,如图一次函数y1=ax+b与反比例函数y2= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象如图示,当y1y2时,x的取值范围是(  )

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

10题图

Ax2 Bx5 C2x5 D0x2x5

8.在同一直角坐标平面内,如果直线y=k1x与双曲线 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 没有交点,那么k1k2的关系一定是(  )

Ak1+k2=0 Bk1•k20 Ck1•k20 Dk1=k2


9.在温度不变的条件下,通过一次又一次地对汽缸顶部的活塞加压,测出每一次加压后缸内气体的体积和气体对汽缸壁所产生的压强,如下表:则可以反映yx之间的关系的式子是(  )

体积xmL

100

80

60

40

20

压强ykPa

60

75

100

150

300

Ay=3 000x By=6 000x Cy= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> Dy= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

10.教室里的饮水机接通电源就进入自动程序,开机加热时每分钟上升10℃,加热100℃,停止加热,水温开始下降,此时水温(℃)与开机后用时(min)成反比例关系.直至水温降至30℃,饮水机关机.饮水机关机后即刻自动开机,重复上述自动程序.若在水温为30℃时,接通电源后,水温y(℃)和时间(min)的关系如图,为了在上午第一节下课时(825)能喝到不小于70℃的水,则接通电源的时间可以是当天上午的(  )


A700 B710 C725 D735

 

二.填空题(共8小题)

11.在①y=2x﹣1;②y=﹣ <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ;③y=5x﹣3;④y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 中,yx的反比例函数的有

      (填序号).

1 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 2.(2016•邵阳)已知反比例函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k0)的图象如图所示,则k的值可能是      (写一个即可).







13.如图是三个反比例函数的图象的分支,其中k1k2k3的大小关系是      

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

13题图




14题图



14.如图,正比例函数y=ax的图象与反比例函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象相交于点AB,若点A的坐标为

(﹣23),则点B的坐标为      


15.已知反比例函数y=﹣ <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,则有

它的图象在一、三象限:

点(﹣24)在它的图象上;

lx2时,y的取值范围是﹣8y<﹣4

若该函数的图象上有两个点A x1y1),Bx2y2),那么当x1x2时,y1y2

以上叙述正确的是      


16.(2016•荆州)若12xm﹣1y23xyn+1是同类项,点Pmn)在双曲线 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 上,则a的值为      


17.一定质量的二氧化碳,其体积Vm3)是密度ρkg/m3)的反比例函数,请你根据图中的已知条件,写出反比例函数的关系式,当V=1.9m3时,ρ=      

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

17题图

18题图


18.在平面直角坐标系中,直线y=﹣x+2与反比例函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象有唯一公共点,若直线y=﹣x+b与反比例函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象有2个公共点,则b的取值范围是      


 

三.解答题(共6小题)


19.己知函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 为反比例函数.

1)求k的值;

2)它的图象在第      象限内,在各象限内,yx增大而      ;(填变化情况)

3)求出﹣2x <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 时,y的取值范围.







20.在平面直角坐标系xOy中,反比例函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k0)的图象经过点A2m),连接OA,在x轴上有一点B,且AO=AB,△AOB的面积为2

1)求mk的值;

2)若过点A的直线与y轴交于点C,且∠ACO=30°,请直接写出点C的坐标.

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>




21.(2016•广安)如图,一次函数y1=kx+bk0)和反比例函数y2= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> m0)的图象交于点A(﹣16),Ba,﹣2).

1)求一次函数与反比例函数的解析式;

2)根据图象直接写出y1y2时,x的取值范围.

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>




22.如图,在平面直角坐标系xOy中,菱形OABC的顶点Ax轴的正半轴上,反比例函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象经过点C3m).

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 1)求菱形OABC的周长;

2)求点B的坐标.







23.某物流公司要把3000吨货物从M市运到W市.(每日的运输量为固定值)

1)从运输开始,每天运输的货物吨数y(单位:吨)与运输时间x(单位:天)之间有怎样的函数关系式?

2)因受到沿线道路改扩建工程影响,实际每天的运输量比原计划少20%,以致推迟1天完成运输任务,求原计划完成运输任务的天数.








24.已知反比例函数 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 和一次函数y=2x﹣1,其中一次函数的图象经过(ab),(a+kb+k+2)两点.

1)求反比例函数的解析式;

2)求反比例函数与一次函数两个交点AB的坐标:

3)根据函数图象,求不等式 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>2x﹣1的解集;

4)在(2)的条件下,x轴上是否存在点P,使△AOP为等腰三角形?若存在,把符合条件的P点坐标都求出来;若不存在,请说明理由.

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

 


参考答案

 

一.选择题(共10小题)

1B2C3D4C5D6D7D8B9D10B


 

二.填空题(共8小题)

11 ①④ (填序号). 12 ﹣1 (写一个即可). 13 k1k3k2 


14 (2,﹣3) 15 ②③ 16 3 17 5kg/m3 


 

18 b2b2 


 

三.解答题(共6小题)

19.己知函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 为反比例函数.

1)求k的值;

2)它的图象在第 二、四 象限内,在各象限内,yx增大而 增大 ;(填变化情况)

3)求出﹣2x <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 时,y的取值范围.

【解答】解:(1)由题意得:k2﹣5=﹣1

解得:k=±2

k﹣20

k=﹣2

2)∵k=﹣20

反比例函数的图象在二、四象限,在各象限内,y随着x增大而增大;

故答案为:二、四,增大;

3)∵反比例函数表达式为 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

x=﹣2时,y=2,当 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 时,y=8

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 时,2y8

 

20.在平面直角坐标系xOy中,反比例函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> k0)的图象经过点A2m),连接OA,在x轴上有一点B,且AO=AB,△AOB的面积为2

1)求mk的值;

2)若过点A的直线与y轴交于点C,且∠ACO=30°,请直接写出点C的坐标.

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【解答】解:(1)由题意可知B40),

AAHx轴于H

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> AH=mOB=4

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

m=1

A21),

k=2

2C01+ <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> )或C01﹣ <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

 

21.(2016•广安)如图,一次函数y1=kx+bk0)和反比例函数y2= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> m0)的图象交于点A(﹣16),Ba,﹣2).

1)求一次函数与反比例函数的解析式;

2)根据图象直接写出y1y2时,x的取值范围.

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【解答】解:(1)把点A(﹣16)代入反比例函数y2= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> m0)得:

m=﹣1×6=﹣6

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

Ba,﹣2)代入 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 得:

2= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

a=3

B3,﹣2),

A(﹣16),B3,﹣2)代入一次函数y1=kx+b得:

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

y1=﹣2x+4

2)由函数图象可得:x<﹣10x3

 

22.如图,在平面直角坐标系xOy中,菱形OABC的顶点Ax轴的正半轴上,反比例函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象经过点C3m).

1)求菱形OABC的周长;

2)求点B的坐标.

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【解答】解:(1)∵反比例函数y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 的图象经过点C3m),

m=4

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> CDx轴于点D,如图1

由勾股定理,得OC= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> =5

菱形OABC的周长是20


2)作BEx轴于点E,如图2

BC=OA=5OD=3

OE=8

又∵BCOA

BE=CD=4

B84).


23.某物流公司要把3000吨货物从M市运到W市.(每日的运输量为固定值)

1)从运输开始,每天运输的货物吨数y(单位:吨)与运输时间x(单位:天)之间有怎样的函数关系式?

2)因受到沿线道路改扩建工程影响,实际每天的运输量比原计划少20%,以致推迟1天完成运输任务,求原计划完成运输任务的天数.

【解答】解:(1)∵每天运量×天数=总运量

xy=3000

y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> x0);


2)设原计划x天完成,根据题意得:

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 1﹣20%= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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=4

经检验:x=4是原方程的根,

答:原计划4天完成.

 

24.已知反比例函数 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> 和一次函数y=2x﹣1,其中一次函数的图象经过(ab),(a+kb+k+2)两点.

1)求反比例函数的解析式;

2)求反比例函数与一次函数两个交点AB的坐标:

3)根据函数图象,求不等式 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>2x﹣1的解集;

4)在(2)的条件下,x轴上是否存在点P,使△AOP为等腰三角形?若存在,把符合条件的P点坐标都求出来;若不存在,请说明理由.

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

【解答】解:(1)∵一次函数的图象经过(ab),(a+kb+k+2)两点,

b=2a﹣1①2a+2k﹣1=b+k+2②

整理②得:b=2a﹣1+k﹣2

由①②得:2a﹣1=2a﹣1+k﹣2

k﹣2=0

k=2

反比例函数的解析式为:y= <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>


2)解方程组 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

A11),B <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a> ,﹣2);


3)根据函数图象,可得出不等式 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>2x﹣1的解集;

0x1x <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>


4)当AP1x轴,AP1=OP1,∴P110),

AO=OP2,∴P2 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>0),

AO=AP3,∴P320),

AO=P4O,∴P4(﹣ <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>0).

存在PP110),P2 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>0),P320),P4(﹣ <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" 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/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/411/" title="反比例" class="c1" target="_blank">反比例</a> <a href="/tags/885/" title="函数" class="c1" target="_blank">函数</a>

 


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