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> (1)计算:-22+(12-1)0+2sin30°(2)先化简,再求值x2-1x2-2x+1+x2-2xx-2÷x,其中x=12.-数学
(1)计算:-22+(12-1)0+2sin30°(2)先化简,再求值x2-1x2-2x+1+x2-2xx-2÷x,其中x=12.-数学
题目简介
(1)计算:-22+(12-1)0+2sin30°(2)先化简,再求值x2-1x2-2x+1+x2-2xx-2÷x,其中x=12.-数学
题目详情
(1)计算:-2
2
+
(
1
2
-1
)
0
+2sin30°
(2)先化简,再求值
x
2
-1
x
2
-2x+1
+
x
2
-2x
x-2
÷x
,其中x=
1
2
.
题型:解答题
难度:中档
来源:不详
答案
(1)原式=-4+1+2×
class="stub"1
2
=-4+1+1
=-2;
(2)∵x=
class="stub"1
2
,
∴原式=
(x+1)(x-1)
(x-1)
2
+
x(x-2)
x-2
×
class="stub"1
x
,
=
class="stub"x+1
x-1
+1,
=
class="stub"x+1
x-1
+
class="stub"x-1
x-1
,
=
class="stub"2x
x-1
,
=
2×
class="stub"1
2
class="stub"1
2
-1
,
=-2.
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题目简介
(1)计算:-22+(12-1)0+2sin30°(2)先化简,再求值x2-1x2-2x+1+x2-2xx-2÷x,其中x=12.-数学
题目详情
(2)先化简,再求值
答案
=-4+1+1
=-2;
(2)∵x=
∴原式=
=
=
=
=
=-2.