(1)先化简,再求值:(x-xx+1)÷(1+1x2-1),其中x=2+1(2)计算:-32+(-3)-2+(2×106)×(1×10-5)+(π-3)0.-数学

题目简介

(1)先化简,再求值:(x-xx+1)÷(1+1x2-1),其中x=2+1(2)计算:-32+(-3)-2+(2×106)×(1×10-5)+(π-3)0.-数学

题目详情

(1)先化简,再求值:(x-
x
x+1
)÷(1+
1
x2-1
),其中x=
2
+1

(2)计算:-32+(-3)-2+(2×106)×(1×10-5)+(π-3)0
题型:解答题难度:中档来源:不详

答案

(1)原式=
x2
x+1
÷
x2
x2-1
=
x2
x+1
(x+1)(x-1)
x2
=x-1,
将x=
2
+1时,原式=
2
+1-1=
2


(2)原式=-9+class="stub"1
9
+2×10+1=12class="stub"1
9

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