题目内容
(2011•崇川区模拟)(1)计算(
)-2-
sin60°+(
-1)0
(2)化简:(
-x-1)÷
.
1 |
2 |
27 |
2 |
(2)化简:(
3 |
x-1 |
x-2 |
x2-x |
分析:(1)分别计算(
)-2=4,
=3
,sin60°=
,(
-1)0=1,代入求出即可;
(2)算括号里面的,同时把除法变成乘法,再分解因式后约分即可.
1 |
2 |
27 |
3 |
| ||
2 |
2 |
(2)算括号里面的,同时把除法变成乘法,再分解因式后约分即可.
解答:解:(1)原式=4-3
×
+1=5-
=
;
(2)原式=
×
=
×
=
×
=-x(x+2)
=-x2-2x.
3 |
| ||
2 |
9 |
2 |
1 |
2 |
(2)原式=
3-(x+1)(x-1) |
x-1 |
x(x-1) |
x-2 |
=
4-x2 |
x-1 |
x(x-1) |
x-2 |
=
-(x+2)(x-2) |
x-1 |
x(x-1) |
x-2 |
=-x(x+2)
=-x2-2x.
点评:本题考查了分式的混合运算、零指数幂、负指数幂、特特殊角的三角函数等知识点的理解和运用,能熟练地根据法则进行计算是解此题的关键.
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