由y=1+2sin(1-x/1+x)有
(1-x)/(1+x)=arcsin(y-1)
1-x=arcsin(y-1)+x*arcsin(y-1)
(1+arcsin(y-1))*x=1-arcsin(y-1)
即,反函数为：x=(1-arcsin(y-1))/(1+arcsin(y-1))