先化简,再求值:(a分之a-1-a 1分之a-2)÷a²+2a+1分之2a²-a.其中a满足a²-a满足a²-a-1=0.
问题描述：
先化简,再求值:(a分之a-1-a 1分之a-2)÷a²+2a+1分之2a²-a.其中a满足a²-a
满足a²-a-1=0.
答
原式=[(a-1)/a -(a-2)/(a+1)]÷ a(2a-1)/(a+1)²=[(a-1)(a+1)-a(a-2)]/a(a+1)× (a+1)²/a(2a-1)=(2a-1)/a(a+1)×(a+1)²/a(2a-1)=(a+1)/a²∵a²-a-1=0∴a²= a+1∴原式=(a+1)/(a+1) =1...