Mathematics Specification B - 4MB1 PearsonEdexcel

Functions And Notation

Overview

A function is a rule for turning one number into another, and once you can name that rule you can start combining rules, reversing them, and asking exactly which inputs are allowed. This topic gives you the notation that makes all of that precise: f(x), f: x → ..., domain, range, composite functions and inverse functions.

These ideas sit underneath almost everything else in the specification, from graph sketching to calculus, so getting the notation fluent now pays off across the whole course.

Objectives

  1. Understand the idea of a function of a variable
  2. Understand a function as a mapping or as a correspondence between the elements of two sets
  3. Use functional notations of the form f(x) = ... and f: x -> ...
  4. Understand and use domain and range of a function
  5. Find and use composite functions
  6. Find and use inverse functions

Lesson Note

Think of a function as a machine. You feed a number in, the machine applies a fixed rule, and a single number comes out. The same input always produces the same output, but two different inputs are allowed to give the same output. This is exactly what a function is: a rule that assigns to every element of one set (the domain) exactly one element of a second set (the range or codomain).

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Lesson Evaluation

Congratulations on completing the lesson on Functions And Notation. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.

You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.

Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.

  1. If f(x) = 3x - 5, what is f(4)? A) 7 B) 12 C) 17 D) -7 Answer: A
  2. If f(x) = x^2 + 1 and g(x) = x - 2, what is fg(3)? A) 2 B) 7 C) 8 D) 10 Answer: A
  3. Which value must be excluded from the domain of h(x) = 1/(x - 6)? A) x = 0 B) x = -6 C) x = 6 D) x = 1 Answer: C
  4. If f(x) = 5x + 2, what is f^-1(x)? A) (x - 2)/5 B) (x + 2)/5 C) 5x - 2 D) x/5 - 2 Answer: A
  5. A function that has an inverse must be: A) many-to-one B) one-to-one C) always increasing D) always positive Answer: B

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Full lesson notes with diagrams
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Available on the Green Bridge App

Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.

Full lesson notes with diagrams
AI-powered learning assistant
Study offline, anytime, anywhere
Available on Android, Windows, macOS, and Linux

Practice Mock Questions

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