计算:(1)计算:2cos45°+(2-1)0-(12)-1(2)化简:(1a-1)÷a2-1a2+a.-数学

题目简介

计算:(1)计算:2cos45°+(2-1)0-(12)-1(2)化简:(1a-1)÷a2-1a2+a.-数学

题目详情

计算:
(1)计算:2cos45°+(
2
-1)0-(
1
2
-1  
(2)化简:(
1
a
-1)÷
a2-1
a2+a
题型:解答题难度:中档来源:不详

答案

(1)原式=2×
2
2
+1-2
=
2
+1-2
=
2
-1;

(2)原式=class="stub"1-a
a
a(a+1)
(a+1)(a-1)

=-class="stub"a-1
a
a(a+1)
(a+1)(a-1)

=-1.

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