A?composite function?is where one function is applied after another function
The ‘output’?of one function will be the ‘input’?of the next one
Sometimes called?function-of-a-function
A composite function can be denoted
?
How do I work with composite functions?
Recognise?the notation
Special cases
fg(x)?and?gf(x)?are generally different but can sometimes be the same
ff(x)?is written as?f2(x)
Inverse functions?ff-1(x) = f-1f(x) = x
Exam Tip
Domain?and?range?are important.In?fg(x), the ‘output’ (range) of?g?must?be in the domain of?f(x), so?fg(x)?could exist, but?gf(x)?may not (or not for some values of x).