1道分式运算
问题描述：
1道分式运算
(X^3+X^2+X)/(X^3-1)+(X^3-X^2+X)/(X^3+1)
答
(X^3+X^2+X)/(X^3-1)+(X^3-X^2+X)/(X^3+1)
= x(x^2+x+1)/(x-1)(x^2+x+1)+x(x^2-x+1)/(x+1)(x^2-x+1)
=x/(x-1)+x/(x+1)
=2x^2/(x-1)(x+1)
=2x^2/(x^2-1)