先化简再求值(a-1)/(a2-2a+1)+(a+1)/(a2-1),其中a=2
问题描述：
先化简再求值(a-1)/(a2-2a+1)+(a+1)/(a2-1),其中a=2
快啊!
答
=(a-1)/(a-1)^2 +(a+1)/(a+1)(a-1) //
=1/(a-1) + 1/(a-1)
=2/(a-1)
=2/(2-1) 把a=2代入
=2