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
The Number e
Problem 1
Textbook Question
In Exercises 1–4, the graph of an exponential function is given. Select the function for each graph from the following options: f(x) = 4^x, g(x) = 4^-x, h(x) = -4^(-x), r(x) = -4^(-x)+3 1. ![Graph of an exponential function with point (0,2) marked.](https://lightcat-files.s3.amazonaws.com/problem_images/ed6ab88e198af581-1671818346246.jpg)
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1
Observe the graph and note that it passes through the point (0, 2).
Identify the general shape of the graph. It is decreasing and approaches a horizontal asymptote.
Compare the graph with the given function options: f(x) = 4^x, g(x) = 4^-x, h(x) = -4^(-x), r(x) = -4^(-x)+3.
Notice that the graph has a horizontal asymptote at y = 2, which suggests a vertical shift.
Select the function r(x) = -4^(-x) + 3, as it matches the observed behavior and vertical shift of the graph.
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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. These functions exhibit rapid growth or decay, depending on whether 'a' is greater than or less than 1. The graph of an exponential function is characterized by a continuous curve that approaches the x-axis but never touches it, known as a horizontal asymptote.
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Graph Characteristics
The graph of an exponential function has distinct characteristics, including a y-intercept at (0, a) and a horizontal asymptote along the x-axis. If the base 'a' is greater than 1, the function increases as x increases; if 'a' is between 0 and 1, the function decreases. The steepness of the curve is influenced by the value of 'a', with larger bases resulting in steeper growth.
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Transformations of Functions
Transformations of functions involve shifting, reflecting, or stretching the graph of a function. For example, a negative exponent indicates a reflection across the y-axis, while adding a constant shifts the graph vertically. Understanding these transformations is crucial for identifying the correct function that matches a given graph, as they alter the basic shape and position of the exponential function.
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