计算a的2次方-1/a2次方+2a+1-a-1/1
问题描述：
计算a的2次方-1/a2次方+2a+1-a-1/1
答
原式=(a-1)(a+1)/(a+1)²-(a-1)/1
=(a-1)/(a+1)-(a-1)/1
=(a-1)/(a+1-1)
=(a-1)/a