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Ch. 2 - Graphs and Functions
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063당신이 사용하는 게 아니라요?교과서 변경
3장, 문제 23c

For the pair of functions defined, find (ƒg)(x). Give the domain of each. See Example 2.
ƒ(x)=√(4x-1), g(x)=1/x

검증된 단계별 안내
1
Identify the composition of functions (ƒg)(x), which means ƒ(g(x)). This involves substituting g(x) into the function ƒ(x).
Write the expression for (ƒg)(x) by replacing x in ƒ(x) with g(x). Since ƒ(x) = \(\sqrt{4x - 1}\) and g(x) = \(\frac{1}{x}\), we have (ƒg)(x) = \(\sqrt{4 \cdot \frac{1}{x}\) - 1}.
Simplify the expression inside the square root: \(\sqrt{\frac{4}{x}\) - 1}.
Determine the domain of g(x) = \(\frac{1}{x}\). Since division by zero is undefined, the domain of g(x) is all real numbers except x = 0.
Determine the domain of (ƒg)(x) by considering the expression inside the square root must be greater than or equal to zero: \(\frac{4}{x}\) - 1 \(\geq\) 0. Solve this inequality along with the domain restriction from g(x) to find the domain of (ƒg)(x).

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주요 개념

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

Function Composition

Function composition involves applying one function to the result of another, denoted as (ƒg)(x) = ƒ(g(x)). It requires substituting the entire output of g(x) into the function ƒ. Understanding this process is essential to correctly combine the two given functions.
추천 영상:
4:56
Function Composition

Domain of a Function

The domain of a function is the set of all input values (x) for which the function is defined. When composing functions, the domain of the composite function depends on the domains of both functions and the values for which the inner function's output fits the outer function's domain.
추천 영상:
3:51
Domain Restrictions of Composed Functions

Square Root and Rational Function Domains

For ƒ(x) = √(4x - 1), the expression inside the square root must be non-negative, so 4x - 1 ≥ 0. For g(x) = 1/x, x cannot be zero because division by zero is undefined. These restrictions are crucial when determining the domains of each function and their composition.
추천 영상:
02:20
Imaginary Roots with the Square Root Property