问题 解答题
先化简,再求值:
x-2
x2-1
÷
2x+2
x2+2x+1
+
1
x-1
,其中x=
2
+1
答案

原式=

x-2
(x+1)(x-1)
÷
2(x+1)
(x+1) 2
+
1
x-1

=

x-2
(x+1)(x-1)
×
x+1
2
+
1
x-1

=

x-2
2(x-1)
+
1
x-1

=

x
2(x-1)

当x=

2
+1,原式=
2+
2
4

判断题
名词解释