计算：a的平方-1分之2+a+1分之1
问题描述：
计算：a的平方-1分之2+a+1分之1
答
2/(a+1)(a-1)+1/(a+1)
=[2-(a-1)]/[(a+1)(a-1)]
=-1/(a+1)
答
2/(a^2-1)+1/(a+1)
=(2+a-1)/(a^2-1)
=(a+1)/(a^2-1)
=1/(a-1)