2/a^2-1 +1/a+1 分式的加减

问题描述:

2/a^2-1 +1/a+1 分式的加减

=2/(a-1)(a+1) +(a-1)/(a+1)(a-1)
=(2+a-1)/(a-1)(a+1)
=(a+1)/(a-1)(a+1)
=1/(a-1)