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Ch. 4 - Inverse, Exponential, and Logarithmic Functions
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063당신이 사용하는 게 아니라요?교과서 변경
5장, 문제 51

Graph each function. Give the domain and range. See Example 3. ƒ(x) = (1/3)x - 2

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Identify the base function and its transformation. The given function is \(f(x) = \left(\frac{1}{3}\right)^x - 2\), which is an exponential function with base \(\frac{1}{3}\) and a vertical shift downward by 2 units.
Recall the general shape and properties of the base function \(g(x) = \left(\frac{1}{3}\right)^x\). Since \(0 < \frac{1}{3} < 1\), this is an exponential decay function that approaches zero as \(x\) approaches infinity and grows without bound as \(x\) approaches negative infinity.
Apply the vertical shift to the base function. The graph of \(f(x)\) is the graph of \(g(x)\) shifted down by 2 units. This means every \(y\)-value of \(g(x)\) is decreased by 2.
Determine the domain of \(f(x)\). Since exponential functions are defined for all real numbers, the domain is all real numbers, expressed as \((-\infty, \infty)\).
Determine the range of \(f(x)\). The base function \(g(x)\) has range \((0, \infty)\), so after shifting down by 2, the range becomes \((-2, \infty)\). This means the graph approaches the horizontal asymptote \(y = -2\) but never touches or goes below it.

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Exponential Functions

An exponential function has the form f(x) = a^x, where the base a is a positive constant not equal to 1. It models rapid growth or decay depending on whether the base is greater than or less than 1. Understanding its shape helps in graphing and analyzing behavior.
추천 영상:
6:13
Exponential Functions

Domain and Range of Functions

The domain is the set of all possible input values (x-values) for which the function is defined, while the range is the set of all possible output values (f(x)). For exponential functions, the domain is usually all real numbers, and the range depends on vertical shifts and transformations.
추천 영상:
4:22
Domain & Range of Transformed Functions

Graphing Transformations

Graphing transformations involve shifting, stretching, or reflecting the base graph. For f(x) = (1/3)^x - 2, subtracting 2 shifts the graph downward by 2 units, affecting the range but not the domain. Recognizing these changes is key to accurately sketching the function.
추천 영상:
5:25
Intro to Transformations