一個反函數的問題

y=2x/(5x+1)
y(5x+1)=2x
5xy+y=2x
5xy-2x=-y
x(5y-2)=-y
x=y/(2-5y)

2006-12-05 23:57:04 補充：
y=(x-1)/(x+1)y(x+1)=x-1xy+y=x-1xy-x=-(1+y)x(y-1)=-(1+y)x=(1+y)/(1-y)

這也是主項轉移的問題

y = (2x) / (5x + 1)
y (5x + 1) = 2x
5xy + y = 2x
y = 2x - 5xy
y = x (2 - 5y)
y / (2 - 5y) = x

x = y / (2 - 5y)