先化简1-a-1/a÷a²-1/a²+2a,在选取一个合适的值代入计算

先化简1-a-1/a÷a²-1/a²+2a,在选取一个合适的值代入计算
先化简1-a-1/a÷a²-1/a²+2a,在选取一个合适的值代入计算

先化简1-a-1/a÷a²-1/a²+2a,在选取一个合适的值代入计算
1-(a-1)/a×a(a+2)/(a+1)(a-1)
=1-(a+2)/(a+1)
=[(a+1)-(a+2)]/(a+1)
=-1/(a+2)
取a=0
∴原式=-1/(0+2)=-1/2