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Ch. 4 - Exponential and Logarithmic Functions
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 5, Problem 45

Graph f(x) = (1/2)x and g(x) = log1/2 x in the same rectangular coordinate system.

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Identify the functions to be graphed: \(f(x) = \left(\frac{1}{2}\right)^x\) is an exponential function with base \(\frac{1}{2}\), and \(g(x) = \log_{\frac{1}{2}}(x)\) is the logarithmic function with base \(\frac{1}{2}\).
Recall that the graph of \(f(x) = a^x\) where \$0 < a < 1\( is a decreasing exponential curve that passes through the point \)(0,1)$ because any nonzero number raised to the zero power is 1.
For \(g(x) = \log_a(x)\) where \$0 < a < 1\(, the graph is the inverse of the exponential function \)f(x) = a^x\(. This means the graph of \)g(x)\( is a reflection of \)f(x)\( across the line \)y = x$.
Determine key points for \(f(x)\) by substituting values such as \(x = -1, 0, 1, 2\) to get points like \((x, f(x))\). Similarly, find points for \(g(x)\) by choosing \(x\) values and calculating \(g(x)\), keeping in mind the domain of \(g(x)\) is \(x > 0\).
Plot the points for both functions on the same coordinate system, draw smooth curves through these points, and include the line \(y = x\) to visualize the reflection relationship between \(f(x)\) and \(g(x)\).

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Key Concepts

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

Exponential Functions

An exponential function has the form f(x) = a^x, where the base a is a positive constant. In this question, f(x) = (1/2)^x represents exponential decay since the base is between 0 and 1. Understanding how the graph behaves, including its asymptote and decreasing nature, is essential for plotting it accurately.
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Exponential Functions

Logarithmic Functions

A logarithmic function is the inverse of an exponential function and is written as g(x) = log_a(x), where a is the base. Here, g(x) = log_(1/2)(x) is the logarithm with base 1/2, which is less than 1, causing the graph to decrease and reflect the inverse behavior of the exponential function. Recognizing domain restrictions and shape is key.
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Graphs of Logarithmic Functions

Inverse Functions and Their Graphs

Exponential and logarithmic functions with the same base are inverses, meaning their graphs are reflections across the line y = x. Understanding this relationship helps in graphing both functions on the same coordinate system and predicting their intersection and symmetry properties.
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Graphs of Logarithmic Functions
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