Mathematics

Problem

For a real function

f:\mathbb{R}\to\mathbb{R}

, which of the following conditions guarantees that the inverse

f^{-1}

exists and is also a function? a)

f

is strictly increasing on

\mathbb R

f

is one-to-one only c)

f

is both one-to-one and onto d)

f

is continuous and differentiable on

\mathbb R