Question

(a²-1/a-1+1)÷a+1+×a²-1/a²+2a,在求值,其中a=2

Answer 1

原式=[(a+1)(a-1)/(a-1)+1]÷(a+1)×(a+1)(a-1)/a(a+2)

=(a+1+1)/(a+1)×(a+1)(a-1)/a(a+2)

=(a-1)/a

当a=2时,原式=（2-1）/2=1/2