(1)计算:-22+(tan60°-1)×3+(-12)-2+(-π)0-|2-3|(2)先化简,再求值:a+1a-1-aa2-2a+1÷1a,其中a=1-2.-数学

题目简介

(1)计算:-22+(tan60°-1)×3+(-12)-2+(-π)0-|2-3|(2)先化简,再求值:a+1a-1-aa2-2a+1÷1a,其中a=1-2.-数学

题目详情

(1)计算:-22+(tan60°-1)×
3
+(-
1
2
)
-2
+(-π)0-|2-
3
|

(2)先化简,再求值:
a+1
a-1
-
a
a2-2a+1
÷
1
a
,其中a=1-
2
题型:解答题难度:中档来源:不详

答案

(1)-22+(tan60°-1)×
3
+(-class="stub"1
2
)
-2
+(-π)0-|2-
3
|
=-4+3-
3
+4+1-2+
3
=2;
(2)class="stub"a+1
a-1
-class="stub"a
a2-2a+1
÷class="stub"1
a
=class="stub"a+1
a-1
-class="stub"a
(a-1)2
×a=class="stub"a+1
a-1
-
a2
(a-1)2
=
a2-1-a2
(a-1)2
=-class="stub"1
(a-1)2

a=1-
2
代入上式得:
原式=-class="stub"1
(1-
2
-1)2
=-class="stub"1
2

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