求y=(1+x)/(1-x) 的反函数的详细解法

问题描述:

求y=(1+x)/(1-x) 的反函数的详细解法

y=(1+x)/(1-x)
y(1-x)=1+x
y-xy=1+x
xy-x=1+y
x(y-1)=1+y
x=(y+1)/(y-1)
则反函数是y=(x+1)/(x-1) (x≠1)原式是 y=(1+x)/(1-x)答案是 y= (x-1)/(x+1)y=(1+x)/(1-x)y(1-x)=1+xy-xy=1+xx+xy=y-1x(y+1)=y-1x=(y-1)/(y+1)则反函数是y=(x-1)/(x+1)(x≠-1)