（x-x/x+1） 除 （1+1/x的平方-1） 其中x=根號2+1
= （1+1/x的平方-1）/ （x-x/x+1）
= (x^2-1+1)/(x^2-1) / (x(x+1)-x)/(x+1)
= (x^2/(x+1)(x-1)) * (x+1)/(x^2+x-x)
= (x^2/(x+1)(x-1)) * (x+1)/(x^2)
=1/(x-1)
=1/(√2+1-1)
=√2/2
計算;(1+x的平方-1/x的平方-2x+1)除1/x-1
=1/(x-1) / (1+(x+1)(x-1)/(x-1)^2)
=1/(x-1) / (1+(x+1)/(x-1))
=1/(x-1) / ((x-1+x+1)/(x-1))
=1/(x-1) * (x-1)/2x
=1/2x
解方程：x的平方-3x / x的平方-1-x+1/x-1=0
(x^2-3x)-(x+1)^2=0
x^2-3x-x^2-2x-1=0
5x=-1
x=-1/5
經(jīng)驗證x=-1/5是方程的解