Question

为什么y=(x+1)/(x+2)的反函数为:x=(1－2y)/（y－1）,怎么求呢

Answer 1

y=(x+1)/(x+2)

x+1=xy+2y

x-xy=2y-1

x(1-y)=2y-1

x=(2y-1)/(1-y)=(1-2y)/(y-1)