Mathematics Advanced Year 11 - Module 1 - Lesson 6
Inverse Functions
1. Key Ideas
Every time you unlock your phone with a passcode, encryption turns your code into something unreadable — and only the inverse process can turn it back. That is the power of an inverse function: it undoes what the original function did, perfectly and predictably.
- The definition of an inverse function
- Why an inverse swaps the domain and range
2. Success Criteria
By the end, you should be able to:
- The definition of an inverse function
- The algebraic method for finding an inverse
- That $f(f^{-1}(x)) = x$
3. Key Terms
4. Activity: Build the Lesson Map
Use the lesson to complete the table. Keep answers brief but specific.
| Prompt | Your answer |
|---|---|
| Main concept | |
| Important example | |
| Common mistake to avoid | |
| How this links to the next lesson |
5. Short Answer Questions
1. Explain this lesson goal in your own words: "The definition of an inverse function". Use one specific example from the lesson.
2. Apply this idea to a new example: "The algebraic method for finding an inverse". Show your reasoning clearly.
3. Analyse why this idea matters for understanding Inverse Functions: "That $f(f^{-1}(x)) = x$".
6. Extend: Apply the Idea
A student gives a memorised answer about Inverse Functions but does not use evidence or reasoning.
Improve the answer by writing a stronger response that uses accurate terminology, a relevant example and a clear explanation.
7. Multiple Choice
1. What is the best first step when answering a question about Inverse Functions?
A. Identify the key concept being tested
B. Write every fact from memory
C. Ignore the command word
D. Skip examples and evidence
2. Which answer would show stronger understanding of Inverse Functions?
A. An answer with accurate terms and reasoning
B. A copied definition only
C. A single-word response
D. An answer with no example
3. What should you do if a question asks you to explain?
A. Link the idea to a reason or cause
B. List unrelated facts
C. Only draw a diagram
D. Write the shortest possible answer
8. Success Criteria Proof
Finish with evidence that you can do each success criterion.