问题 解答题
计算:
(1)
1
a-1
-
2
1-a2
;                      
(2)
a-1
a2-1
+
a
a+1
答案

(1)原式=

a+1
(a-1)(a+1)
+
2
(a-1)(a+1)

=

2+a+1
(a-1)(a+1)

=

a+3
a2-1

(2)原式=

a-1
(a+1)(a-1)
+
a
a+1

=

1
a+1
+
a
a+1

=

a+1
a+1

=1.

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