2.8 Algebra of Functions and Composition

Miller & Gerken, College Algebra 2e — Pages 298-311

Learning Objectives

  • Perform arithmetic operations on functions

  • Find the composition of functions

  • Find the domain of combined functions

  • Decompose functions

Key Concepts

Function Operations

Operation Definition

Sum

\((f + g)(x) = f(x) + g(x)\)

Difference

\((f - g)(x) = f(x) - g(x)\)

Product

\((fg)(x) = f(x) \cdot g(x)\)

Quotient

\(\left(\frac{f}{g}\right)(x) = \frac{f(x)}{g(x)}, \quad g(x) \neq 0\)

Composition

\[(f \circ g)(x) = f(g(x))\]

Read as "f of g of x" — apply \(g\) first, then \(f\).

Domain of Composition

\(x\) must be in domain of \(g\), AND \(g(x)\) must be in domain of \(f\).

Examples

Example 1. Example 1

Work through textbook example…​

Practice Problems

Problem 1 (p. XX, #YY)

Problem:

My Work:

Answer:

Section Summary

  1. Key point 1

  2. Key point 2