This key facts covers Key Facts within Composite Functions for GCSE Mathematics. Revise Composite Functions in Algebra for GCSE Mathematics with 14 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 2 of 7 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 2 of 7
Practice
14 questions
Recall
12 flashcards
Key Facts
| Concept | Meaning | Example |
|---|---|---|
| fg(x) | f of g(x) - do g first, then f | Apply g, then apply f to result |
| gf(x) | g of f(x) - do f first, then g | Apply f, then apply g to result |
| ff(x) | f of f(x) - apply f twice | Do f, then do f again |
| Order matters | fg(x) ≠ gf(x) usually | Different order = different result |
Key insight: fg(x) ≠ gf(x) in general! Order matters!