已知x等于根号2加1,求x+1-x^2除x-1的值
问题描述：
已知x等于根号2加1,求x+1-x^2除x-1的值
答
x+1-x^2除x-1=(x+1)(x-1)/(x-1)-x^2除x-1
=x^2-1/(x-1)-x^2/(x-1)
=-1/(x-1)
=1/(1-x)
x等于根号2加1所以x+1-x^2除x-1=1/(1-x)
=-根号2/2无