先化简再求值 （x+1分之x +x^2-1分之x+1)除以(x^2+x分之x^2+1)

（x+1分之x +x^2-1分之x+1)除以(x^2+x分之x^2+1)
=（x/x+1 +x+1/(x+1)(x-1))/(x^2+1/x^2+x)
=（x/x+1 +1/x-1)*(x^2+x/x^2+1)
=（(x(x-1)+1)/(x+1)(x-1))*(x^2+x/(x^2+1))
=（(x^2-x+1)/(x+1)(x-1))*(x(x+1)/(x^2+1))
=x(x^2-x+1)/(x-1)(x^2+1)
=(x^3-x^2+x)/(x^3+x-x^2-1)
=(x^3-x^2+x-1+1)/(x^3-x^2+x-1)
=1+1/(x^3-x^2+x-1)
再将x的值代入,就可计算了.但他的答案怎么是x-1分之x。。。。不好意思，算错了。 应是 （x+1分之x +x^2-1分之x+1)除以(x^2+x分之x^2+1) =（x/x+1 +x+1/(x+1)(x-1))/(x^2+1/x^2+x) =（x/x+1 +1/x-1)*(x^2+x/x^2+1) =（(x(x-1)+x+1)/(x+1)(x-1))*(x^2+x/(x^2+1)) =（(x^2-x+x+1)/(x+1)(x-1))*(x(x+1)/(x^2+1)) =x(x^2+1)/(x-1)(x^2+1) =x/(x-1)