Formulas

Functions Formulas – IGCSE Maths

Every functions formula you need for Cambridge IGCSE Mathematics 0580, with clear explanations of when and how to use each one.

Composite

Extended

fg(x) = f\!\big(g(x)\big)

Key formula for functions in IGCSE Maths.

Use when working with functions problems.

Show your substitution clearly for method marks.

Extended

\text{Swap } x \text{ and } y\text{, then solve for } y

Key formula for functions in IGCSE Maths.

Use when working with functions problems.

Show your substitution clearly for method marks.

Extended

\text{Set of valid input values}

Key formula for functions in IGCSE Maths.

Use when working with functions problems.

Show your substitution clearly for method marks.

Extended

\text{Set of possible output values}

Key formula for functions in IGCSE Maths.

Use when working with functions problems.

Show your substitution clearly for method marks.

Struggling to remember these formulas?

Teacher Rig helps students master them through practice, not memorisation.

Which functions formulas are given in the exam?

Check the IGCSE formula sheet provided in your exam. Some functions formulas must be memorised.

How do I remember functions formulas?

Practice using them in past paper questions. Repeated application is more effective than rote memorisation.

Book a free trial class with Teacher Rig for personalised formula practice.