Question

A function is called a self-inverse function when which condition holds?

Options

• Its inverse is the exact same as the original function.

• Its domain and codomain are empty.

• It is onto but not one-one.

• Its graph is parallel to the line \(y=x\).

Answer 1

A self-inverse function is unchanged when its inverse is taken. Equivalently, applying the function twice gives the original input, so \((f\circ f)(x)=x\).