Mathematics for IGCSE & O level - Functions (Section 2 - No. 27)

What is the general form of an inverse function?

f(x) = y

f^-1(y)=x

f^-1(x) = y

f(y)=x

If y=f(x), then f^-1(y)=x, and if we swap x and y, the general form is f^-1(x) = y.