数学计算题：(x的平方+x-2)分之(1-x)÷(x+2)分之（x的平方-1)
问题描述：
数学计算题：(x的平方+x-2)分之(1-x)÷(x+2)分之（x的平方-1)
答
=（1-x的平方）分之1
答
(1-x)/(x²+x-2)÷(x²-1)/(x+2)=(1-x)/[(x+2)(x-1)×(x+2)/[(x+1)(x-1)=1/(x+1)(x-1)
答
=-(x-1)/(x+2)(x-1)× (x+2)/(x+1)(x-1)
=-1/(x+1)(x-1)
=-1/(x²-1)
=1/(1-x²)