Functions

## Functions

You need to be able to work with function notation confidently in your exam

## Composite functions

If you apply two functions one after the other, you can write a single function which has the same effect as the two combined functions

This is called a composite function

## Working it out

Order is important in composite functions

You can think of fg(x) as f(g(x))

You work out g(x) first then you use this answer as your input for f(x)

To find an algebraic expression for fg(x) you need to substitute the whole expression for g(x) for each instance of x in the expression for f(x)

# Functions

## Functions

You need to be able to work with function notation confidently in your exam

## Composite functions

If you apply two functions one after the other, you can write a single function which has the same effect as the two combined functions

This is called a composite function

## Working it out

Order is important in composite functions

You can think of fg(x) as f(g(x))

You work out g(x) first then you use this answer as your input for f(x)

To find an algebraic expression for fg(x) you need to substitute the whole expression for g(x) for each instance of x in the expression for f(x)