MEPX
Chapter 9 of 10All chapters
  1. 1Why letters
  2. 2Rearranging
  3. 3Expanding and factorising
  4. 4Straight lines
  5. 5Quadratics
  6. 6Fractions and powers
  7. 7Two unknowns
  8. 8Inequalities
  9. 9Functions
  10. 10Turning words into algebra

Chapter 9 of 10

Functions

A machine with an input and an output.

Notation

f(x) names a rule: give it an x and it returns a value. The graph is just every input paired with its output.

  • Domain is the set of allowed inputs, range is the set of possible outputs.
  • Composing functions applies one to the result of another.

Transformations

Adding outside the function moves the graph up, adding inside moves it sideways, and multiplying stretches it. Recognising those four moves explains most graph questions.