Match the function with its graph from choices A–F. ƒ(x) = log2 x
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- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
6. Exponential & Logarithmic Functions
Introduction to Logarithms
Problem 53
Textbook Question
Begin by graphing f(x) = log₂ x. Then use transformations of this graph to graph the given function. What is the vertical asymptote? Use the graphs to determine each function's domain and range. g(x) = log₂ (x + 1)
Verified step by step guidance1
Start by understanding the base function: \(f(x) = \log_{2} x\). This function has a vertical asymptote at \(x = 0\), a domain of \((0, \infty)\), and a range of \((-\infty, \infty)\).
Next, analyze the given function \(g(x) = \log_{2} (x + 1)\). Notice that the input to the logarithm is shifted by \(+1\), which means the graph of \(f(x)\) is shifted horizontally to the left by 1 unit.
Determine the new vertical asymptote by setting the inside of the logarithm equal to zero: \(x + 1 = 0\). Solve for \(x\) to find the vertical asymptote at \(x = -1\).
Use the horizontal shift to find the domain of \(g(x)\). Since the logarithm requires the argument to be positive, set \(x + 1 > 0\) and solve for \(x\). This gives the domain as \((-1, \infty)\).
The range of \(g(x)\) remains the same as the base function \(f(x)\) because vertical shifts or horizontal shifts do not affect the range of a logarithmic function. Therefore, the range is \((-\infty, \infty)\).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Logarithmic Functions and Their Graphs
A logarithmic function, such as f(x) = log₂(x), is the inverse of an exponential function. Its graph passes through (1,0) and increases slowly, defined only for positive x-values. Understanding the shape and behavior of the basic log function is essential for applying transformations.
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Graphs of Logarithmic Functions
Transformations of Functions
Transformations involve shifting, stretching, or reflecting the graph of a function. For g(x) = log₂(x + 1), the graph of log₂(x) shifts left by 1 unit. Recognizing how inside-the-function changes affect the graph helps identify new asymptotes, domain, and range.
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Domain & Range of Transformed Functions
Vertical Asymptotes and Domain of Logarithmic Functions
Logarithmic functions have vertical asymptotes where the argument equals zero, since log is undefined for non-positive values. For g(x) = log₂(x + 1), the vertical asymptote is at x = -1, which also defines the domain as all x > -1. The range remains all real numbers.
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Determining Vertical Asymptotes
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