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 61b
Textbook Question
Graph each function. Give the domain and range. ƒ(x) = | log↓2 (x+3) |
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1
Step 1: Understand the function f(x) = | log_2(x+3) |. This is the absolute value of the logarithmic function log base 2 of (x+3).
Step 2: Determine the domain of the function. The expression inside the logarithm, (x+3), must be greater than 0. Solve the inequality x+3 > 0 to find the domain.
Step 3: Solve the inequality x+3 > 0, which gives x > -3. Therefore, the domain of the function is all real numbers greater than -3, or in interval notation, (-3, ∞).
Step 4: Consider the range of the function. Since the function is the absolute value of a logarithm, the output will always be non-negative. The range is [0, ∞).
Step 5: To graph the function, plot the basic shape of log_2(x+3) for x > -3, then reflect any negative values above the x-axis to account for the absolute value, ensuring all y-values are non-negative.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Domain of a Function
The domain of a function refers to the set of all possible input values (x-values) for which the function is defined. For the function ƒ(x) = | log₂(x + 3) |, the argument of the logarithm, x + 3, must be greater than zero, leading to the condition x > -3. Thus, the domain is all real numbers greater than -3.
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Range of a Function
The range of a function is the set of all possible output values (y-values) that the function can produce. In the case of ƒ(x) = | log₂(x + 3) |, since the logarithm can take any real number value and the absolute value function transforms all outputs to non-negative values, the range is all non-negative real numbers, or [0, ∞).
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Graphing Logarithmic Functions
Graphing logarithmic functions involves understanding their general shape and behavior. The function ƒ(x) = log₂(x + 3) will have a vertical asymptote at x = -3 and will increase without bound as x increases. The absolute value modifies the graph, reflecting any negative values above the x-axis, resulting in a graph that is always non-negative.
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