求下列函数的反函数y=4x+3 y=(x+1)/(x-1) x∈R且x≠1
问题描述：
求下列函数的反函数y=4x+3 y=(x+1)/(x-1) x∈R且x≠1
答
y=4x+3
4x=y-3
x=1/4y-3/4
即反函数是y=1/4x-3/4
y=(x+1)/(x-1)
y(x-1)=x+1
xy-y=x+1
xy-x=-y-1
x(y-1)=-y-1
x=(y+1)/(1-y)
即反函数是y=（x+1)/(1-x) (x≠1)
答
y=4x+3
4x=y-3
∴x=y/4-3/4
∴反函数是y=x/4 -3/4
y=(x+1)/(x-1)
y(x-1)=x+1
xy-y=x+1
xy-x=y+1
x(y-1)=y+1
x=(y+1)/(y-1)
∴反函数是y=(x+1)/(x-1) x≠1