a+1分之2-a方-1分之a-2除以a方-2a加1分之a方-2a
问题描述：
a+1分之2-a方-1分之a-2除以a方-2a加1分之a方-2a
答
2/(a+1)-(a-2)/(a^2-1)÷(a^2-2a)/(a^2-2a+1)
=2/(a+1)-(a-2)/(a^2-1)*(a^2-2a+1)/(a^2-2a)
=2/(a+1)-(a-2)/[(a-1)(a+1)]*(a-1)^2/[a(a-2)]
=2/(a+1)-1/[(a-1)(a+1)]*(a-1)^2/a
=2/(a+1)-1/(a+1)*(a-1)/a
=2/(a+1)-(a-1)/a(a+1)
=2a/a(a+1)-(a-1)/a(a+1)
=[2a-(a-1)]/a(a+1)
=(2a-a+1)/a(a+1)
=(a+1)/a(a+1)
=1/a