混合的分式加减计算(a/a-1-a²/a²-1)÷(1-1/a+1)
问题描述：
混合的分式加减计算(a/a-1-a²/a²-1)÷(1-1/a+1)
答
[a/(a-1)-a^2/(a^2-1)]÷[1-1/(a+1)]
=[a(a+1)-a^2]/[(a-1)(a+1)]÷[(a+1-1)/(a+1)]
=a/[(a-1)(a+1)]÷[a/(a+1)]
=a/[(a-1)(a+1)]*(a+1)/a
=1/(a-1)