知道原函數,怎麼求反函數?例如:原函數是y=(3x+1)/(x-2),怎麼求出反函數是y=(2x+1)/(x-3)

知道原函數,怎麼求反函數?例如:原函數是y=(3x+1)/(x-2),怎麼求出反函數是y=(2x+1)/(x-3)

y =(3x + 1)/(x - 2)
xy - 2y = 3x + 1
yx - 3x = 1 + 2y
(y - 3)x = 2y + 1
x =(2y + 1)/(y - 3)
交換x,y:y =(2x + 1)/(x - 3)