(1)计算:2sin60°+(-2009)0-12+(12)-1.(2)先化简,再求值:x+1x÷(x-1+x22x),其中x=2+1.-数学

题目简介

(1)计算:2sin60°+(-2009)0-12+(12)-1.(2)先化简,再求值:x+1x÷(x-1+x22x),其中x=2+1.-数学

题目详情

(1)计算:2sin60°+(-2009)0-
12
+(
1
2
)-1

(2)先化简,再求值:
x+1
x
÷(x-
1+x2
2x
)
,其中x=
2
+1.
题型:解答题难度:中档来源:不详

答案

(1)原式=2×
3
2
+1-2
3
+2=3-
3


(2)原式=class="stub"x+1
x
÷
2x2-1-x2
2x
=class="stub"x+1
x
class="stub"2x
(x+1)(x-1)
=class="stub"2
x-1

当x=
2
+1时,原式=class="stub"2
2
+1-1
=
2

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