即 y = (1-2x-1+1)/(1+2x)=(2-(2x+1)) /(1+2x)=2/(1+2x) - 1 所以 y+1 = 2/(1+2x)1/(y+1) = (1+2x)/2所以有 x = (2/(y+1) -1)/2 = (1-y)/(2(y+1))所以反函数 为 y= (1-x)/(2(x+1))