Question

先化简,再求值:a减1分之1加1减a分之a的和除以a。其中a=根号2加1

要具体过程。不然不给分。

Answer 1

[1/(a-1)+a/(1-a)]/a
=[1/(a-1)-a/(a-1)]/a
=[(1-a)/(a-1)]/a
=-1/a
把a=√2+1代入
-1/(√2+1)
=-1(√2-1)/(√2+1)(√2-1)
=1-√2

Answer 2

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