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【329576】2.6 实数 同步练习2

时间:2025-02-02 18:24:49 作者: 字数:3941字


 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>

2.6 实数

  1. 选择

1.下列实数:  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> , <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>0020020002……,无理数有( )个.

A.2 B.3 C.4 D.5

2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> 表示的意义是( )

A.25的立方根 B.25的平方根

C.25的算术平方根 D.5的算术平方根

3.下列语句正确的是( )

A. 2是-4的平方根; B. 2(2)2的算术平方根;

C. (2)2的平方根是2; D. 8的立方根是±2

4.下列各数中,互为相反数的是( )

A.2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>B.2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>C.2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>D. <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> 2

5.算术平方根等于它本身的数是( )

A . <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> B . <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> C .  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> D .  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>

  1. 某位老师在讲“实数”时,画了一个图(如图1),即“以数轴的单位线段为边做一个正方形,然后以O为圆心,正方形的对角线长为半径画弧交x轴上于一点A”。则OA的长就是 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> 个单位长度,想一想:作这样的图可以说明什么?( )

 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>

A.数轴上的点和有理数一一对应

B.数轴上的点和无理数一一对应

C.数轴上的点和实数一一对应

D.不能说明什么

7.实数abc在数轴上的位置如图2: 则化简  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> 的结果是( )

组合 3

A.abc; B.ab+c; C.a+b+c; D.a+bc

8.绝对值小于5的所有实数的积为 ( )

A.24; B.576; C.0; D. 10

9.若实数x满足|x+x=0,则x是( )。

A. 零或负数 B. 非负数 C. 非零实数 D.负数.

10 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> 的整数部分为a,小数部分为b,则b2( )

提示:无理数运算也同样适合完全平方公式哦!

A2 B20 C206 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> D20+6 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>

二、填空

1.- <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> 的倒数是________,绝对值是________

29的平方根是  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> 的算术平方根是______

3.若 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> =2,则 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> 的值是

4.如果 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> =3,那么(a+32的值为

5.计算: <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>

6 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> .  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>

7.若三角形的三边abc满足a24a+4+ <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> =0,则第三边c的取值范围是_____________

8.计算:

 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> =_____, <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> =_____, <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> =__;…….通过以上计算,试用含n(n为正整数)的式子表示上面运算揭示的规律:__________________

三、解答

1.求下列各式的值:

1 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> ; (2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> ; (3)- <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>





2.已知 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> =x1,求x的值。









3.一个长方体的长为5 cm,宽为2 cm,高为3 cm,而另一个正方体的体积是它的3倍,求这个正方体的棱长(结果精确到0.01 cm).

参考值:4.463=88.7,4.473=89.3,4.483=89.9,4.493=90.5









4.已知三角形的三边abc的长分别为 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> cm <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> cm <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> cm,求这个三角形的周长和面积.











5.如图3所示,某计算装置有一数据入口A和一运算结果的出口B,下表给出的是小红输入的数字及所得的运算结果:

A

0

1

4

9

16

25

36

B

1

0

1

2

3

4

5

若小红输入的数为48,输出的结果应为多少?若小红输入的数字为a,你能用a表示输出结果吗?

组合 9



参考答案

一、BCBAACCCAC

二、1.- <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> 2±3 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> 3.-5 481 5 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> 6472 71<c<5 81,1,1,  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>

三、1.(1 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> 7 2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>3)-0.3

2.因为立方根等于它本身的数是1,1,0,所以有x1=1, x1=1x1=0,

所以x=2,01

3  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> = <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> ≈4.48cm

4.周长= <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> + <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> + <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> =12 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> cm

因为( <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>2+ <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>2=125= <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>2

所以三角形是直角三角形,故面积= <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> × <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> × <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a> =30cm2

5.(1)经观察易得出规律: <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/842/" title="实数" class="c1" target="_blank">实数</a>