问题
解答题
有一道题:“先化简再求值:(
|
答案
(
+x-1 x+1
)÷2x x2-1 1 x2-1
=[
+x-1 x+1
]×(x+1)(x-1)2x (x+1)(x-1)
=(x-1)2+2x
=x2+1
∵当x=-
或x=2008
时,x2的值均为2008,2008
∴小明虽然把x值抄错,但结果也是正确的.
有一道题:“先化简再求值:(
|
(
+x-1 x+1
)÷2x x2-1 1 x2-1
=[
+x-1 x+1
]×(x+1)(x-1)2x (x+1)(x-1)
=(x-1)2+2x
=x2+1
∵当x=-
或x=2008
时,x2的值均为2008,2008
∴小明虽然把x值抄错,但结果也是正确的.