化简
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587022_ST/0.png)
.
对此题有位同学作如下解答:
【解析】
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587022_ST/1.png)
=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587022_ST/2.png)
=(
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587022_ST/3.png)
-
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587022_ST/4.png)
)-(
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587022_ST/5.png)
+
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587022_ST/6.png)
)=-2
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587022_ST/7.png)
.
这位同学的解答正确吗?若不正确,请指出错误原因,并加以改正.
考点分析:
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计算:
(1)
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/0.png)
-
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/1.png)
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/2.png)
-(
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/3.png)
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/4.png)
-2
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/5.png)
);
(2)
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/6.png)
÷
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/7.png)
×(
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/8.png)
-2)+2(
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/9.png)
+1)
;
(3)
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/10.png)
÷(
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/11.png)
)+
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/12.png)
;
(4)10
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/13.png)
×[(
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/14.png)
)
2-(
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587021_ST/15.png)
)
2].
查看答案
下列说法错误的是( )
A.零和负数没有算术平方根
B.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587020_ST/0.png)
是一个非负数,也是二次根式
C.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587020_ST/1.png)
的最小值是4
D.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587020_ST/2.png)
的值一定是0
查看答案
小明的作业上有如下的题目,计算错误的是( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587019_ST/0.png)
=4a
2B.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587019_ST/1.png)
=5
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587019_ST/2.png)
a
C.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587019_ST/3.png)
=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587019_ST/4.png)
D.3
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587019_ST/5.png)
+2
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587019_ST/6.png)
=5
查看答案
如图,正方形网格中,每个小正方形的边长为1,则网格上的三角形ABC中,边长为无理数的边数是( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587018_ST/images0.png)
A.0
B.1
C.2
D.3
查看答案
甲,乙两同学对代数式
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587017_ST/0.png)
(m>0,n>0)分别作了如下变形:
甲:
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587017_ST/1.png)
=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587017_ST/2.png)
=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587017_ST/3.png)
;
乙:
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587017_ST/4.png)
=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587017_ST/5.png)
=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103000046515258786/SYS201311030000465152587017_ST/6.png)
.
关于这两种变形过程的说法正确的是( )
A.甲,乙都正确
B.甲,乙都不正确
C.只有甲正确
D.只有乙正确
查看答案