MA14-02 Maths Watch
Inverse and Composite Functions
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In this lesson
In this video you'll learn about inverse and composite functions for GCSE Maths, with worked examples and the mistakes examiners report. By the end you'll be able to find the composite of two functions and the inverse of a function using input-output machine language, applying board-specific f(x)/fg(x) notation where it is required.
What it covers
- Combining two function machines end to end to form a composite function (feed one machine's output into the next machine as input)
- Finding the inverse of a function by reversing its machine, extending video 1's method to two-step (and occasionally three-step) machines and naming it 'the inverse function'
- The board-specific requirement to write composites and inverses using f(x)/fg(x)/f^-1(x) notation - required at AQA-8300 Higher and Edexcel-1MA1 Higher, explicitly not required at OCR-J560, unstated at Eduqas-C300 Higher - naming which is which
Key words
For: AQA GCSE 8300, Edexcel GCSE 1MA1, Eduqas GCSE C300, OCR GCSE J560
On the specification
| Board | Spec | Statement |
|---|---|---|
| AQA GCSE 8300 | A7 | Where appropriate, interpret simple expressions as functions with inputs and outputs |
| Edexcel GCSE 1MA1 | A7 | Where appropriate, interpret simple expressions as functions with inputs and outputs. |
| Eduqas GCSE C300 | HA7 | Where appropriate, interpret simple expressions as functions with inputs and outputs; interpret the reverse process as the 'inverse function'; interpret the succession of two functions as a 'composite function' |
| OCR GCSE J560 | 6.05a | Interpret, where appropriate, simple expressions as functions with inputs and outputs. |
For teachers
This GCSE Maths lesson teaches inverse and composite functions. By the end, students should be able to find the composite of two functions and the inverse of a function using input-output machine language, applying board-specific f(x)/fg(x) notation where it is required. It works through two worked examples and the mistakes examiners report.