Function Notation
Overview
Mathematics needs a compact, unambiguous way to talk about functions, and that is what function notation provides. The single symbol f(x) packs in the name of the rule, its input, and its output, all at once. Once you are fluent in this shorthand, evaluating, inverting and combining functions becomes clean and quick.
In this lesson you will read and use the notations \(f(x)\) and \(f:x\mapsto\ldots\), evaluate a function at a value, and meet the two operations that build new functions from old: the inverse \(f^{-1}\) and the composite \(fg(x)=f(g(x))\). You will also see what \(f^2(x)\) really means, which is not what many students first guess.
Objectives
- Recognise and use function notation, including f(x), f : x maps to, the inverse f-inverse(x), composite functions fg(x), and f squared (x) meaning f(f(x)).
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Function 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.
- Given f(x) = 2x + 3, what is f(5)? A. 10 B. 13 C. 16 D. 25 Answer: B
- Given f(x) = 2x + 3, what is f(-1)? A. -1 B. 1 C. 2 D. 5 Answer: B
- What does f^2(x) mean for a function f? A. [f(x)]^2 B. f(f(x)) C. 2 f(x) D. f(x) + f(x) Answer: B
- Given f(x) = 2x + 3 and g(x) = x^2, what is fg(x)? A. (2x + 3)^2 B. 2x^2 + 3 C. 4x + 9 D. 2x + 3 Answer: B
- The inverse of f(x) = 2x + 3 is: A. (x - 3)/2 B. (x + 3)/2 C. 1/(2x + 3) D. 2x - 3 Answer: A
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