Inverse functions (AQA GCSE Further Maths): Flashcards

Undoes what original function does

$f^{-1}(x)$

Function must be one-to-one

Each input → unique output and vice versa

To make function one-to-one

Write as $y = f(x)$

Interchange $x$ and $y$

Make $y$ the subject

Reflections across $y = x$

Becomes range of $f^{-1}(x)$

$f(f^{-1}(x)) = x$ and $f^{-1}(f(x)) = x$

Inverse function, NOT rac{1}{f(x)}