比亮剑好好看:当x^2-4x+1=0时,求x^2/(x-1)-(1+1/(x^2-x))

来源:百度文库 编辑:中科新闻网 时间:2024/04/29 08:31:54

x^2/(x-1)-(1+1/(x^2-x))
化简:
=x^3/(x^2-x)-(x^2-x)/(x^2-x)-1/(x^2-x)
=(x^3-x^2+x-1)/(x^2-x)
=(x^2+1)(x-1)/(x(x-1))
=x+1/x

而:x^2-4x+1=0
两边同时除以x
x-4+1/x=0
x+1/x=4

所以x^2/(x-1)-(1+1/(x^2-x))=x+1/x=4

结束