Skip to main content
Ch. 4 - Inverse, Exponential, and Logarithmic Functions
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 5, Problem 98c

Use the various properties of exponential and logarithmic functions to evaluate the expressions in parts (a)–(c). Given ƒ(x) = log2 x, find ƒ(22 log_2 2)

Verified step by step guidance
1
Identify the given function and expression: ƒ(x) = log_2 x, and we need to find ƒ(2^{2 \(\log\)_2 2}).
Recall that ƒ(x) = log_2 x means the function outputs the logarithm base 2 of its input, so ƒ(2^{2 \(\log\)_2 2}) = \(\log\)_2 \(\left\)(2^{2 \(\log\)_2 2}\(\right\)).
Use the logarithmic property \(\log\)_b (a^c) = c \(\log\)_b a to simplify the expression inside the logarithm: \(\log\)_2 \(\left\)(2^{2 \(\log\)_2 2}\(\right\)) = 2 \(\log\)_2 2 \(\times\) \(\log\)_2 2.
Recognize that \(\log\)_2 2 equals 1 because 2 raised to the power 1 is 2.
Substitute \(\log\)_2 2 = 1 back into the expression and simplify the multiplication to find the value of the function at the given input.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Logarithmic Functions and Their Properties

A logarithmic function log_b(x) is the inverse of the exponential function b^x. It satisfies properties such as log_b(b^x) = x and log_b(xy) = log_b(x) + log_b(y), which help simplify expressions involving logs and exponents.
Recommended video:
5:26
Graphs of Logarithmic Functions

Exponential Functions and Their Properties

An exponential function has the form b^x, where b is a positive base not equal to 1. Key properties include b^{m+n} = b^m * b^n and (b^m)^n = b^{mn}, which allow manipulation and simplification of expressions with exponents.
Recommended video:
6:13
Exponential Functions

Inverse Relationship Between Logarithms and Exponents

Logarithms and exponents are inverse operations, meaning log_b(b^x) = x and b^{log_b(x)} = x. This relationship is essential for simplifying expressions where logs and exponents are nested, as in the given function evaluation.
Recommended video:
7:30
Logarithms Introduction