Table of contents
- 0. Review of Algebra4h 16m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 19m
- 10. Combinatorics & Probability1h 45m
6. Exponential & Logarithmic Functions
Introduction to Logarithms
Problem 45
Textbook Question
Graph f(x) = (1/2)^x and g(x) = log(1/2) x in the same rectangular coordinate system.
![](/channels/images/assetPage/verifiedSolution.png)
1
Step 1: Understand the functions. The function \( f(x) = \left(\frac{1}{2}\right)^x \) is an exponential function with a base of \( \frac{1}{2} \), which means it is a decreasing function. The function \( g(x) = \log_{\frac{1}{2}}(x) \) is a logarithmic function with the same base, \( \frac{1}{2} \), which also decreases as \( x \) increases.
Step 2: Identify key points for \( f(x) = \left(\frac{1}{2}\right)^x \). Calculate a few values: \( f(0) = 1 \), \( f(1) = \frac{1}{2} \), \( f(2) = \frac{1}{4} \), and \( f(-1) = 2 \). These points will help in sketching the graph.
Step 3: Identify key points for \( g(x) = \log_{\frac{1}{2}}(x) \). Calculate a few values: \( g(1) = 0 \), \( g(\frac{1}{2}) = 1 \), \( g(\frac{1}{4}) = 2 \), and \( g(2) = -1 \). These points will help in sketching the graph.
Step 4: Plot the points for both functions on the same coordinate system. For \( f(x) \), plot the points (0,1), (1,0.5), (2,0.25), and (-1,2). For \( g(x) \), plot the points (1,0), (0.5,1), (0.25,2), and (2,-1).
Step 5: Draw smooth curves through the points for each function. The graph of \( f(x) = \left(\frac{1}{2}\right)^x \) should show a decreasing exponential curve, while the graph of \( g(x) = \log_{\frac{1}{2}}(x) \) should show a decreasing logarithmic curve. Notice that the graphs are reflections of each other across the line \( y = x \).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Exponential Functions
Exponential functions are mathematical expressions in the form f(x) = a^x, where 'a' is a positive constant. In this case, f(x) = (1/2)^x represents a decreasing exponential function, as the base (1/2) is less than 1. Understanding the behavior of exponential functions is crucial for graphing them, as they exhibit rapid growth or decay depending on the base.
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Logarithmic Functions
Logarithmic functions are the inverses of exponential functions and are expressed as g(x) = log_b(x), where 'b' is the base. For g(x) = log(1/2)(x), the base is 1/2, indicating that this function will decrease as x increases. Recognizing the properties of logarithms, such as their domain and range, is essential for accurately graphing them alongside exponential functions.
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Graphing in Rectangular Coordinate Systems
Graphing in rectangular coordinate systems involves plotting points on a two-dimensional plane defined by an x-axis and a y-axis. Each function's graph is represented by a set of points (x, f(x)) or (x, g(x)). Understanding how to scale the axes and interpret the intersection points of different functions is vital for visualizing their relationships and behaviors in the same coordinate system.
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Graphs & the Rectangular Coordinate System
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