Skip to main content
Ch. 2 - Functions and Graphs
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514당신이 사용하는 게 아니라요?교과서 변경
3장, 문제 10

Find f(g(x)) and g (f(x)) and determine whether each pair of functions ƒ and g are inverses of each other. f(x) = ∛(x − 4) and g(x) = x³ +4

검증된 단계별 안내
1
First, recall that the composition of functions f(g(x)) means substituting g(x) into f(x). So, write down f(g(x)) as f(g(x)) = \(\sqrt\)[3]{g(x) - 4}.
Next, substitute g(x) = x^3 + 4 into the expression for f(g(x)), giving f(g(x)) = \(\sqrt\)[3]{(x^3 + 4) - 4}.
Simplify the expression inside the cube root: (x^3 + 4) - 4 simplifies to x^3, so f(g(x)) = \(\sqrt\)[3]{x^3}.
Now, recall that the cube root of x cubed is just x, so f(g(x)) simplifies to x.
Next, find g(f(x)) by substituting f(x) into g(x). Write g(f(x)) = (f(x))^3 + 4, then substitute f(x) = \(\sqrt\)[3]{x - 4} to get g(f(x)) = (\(\sqrt\)[3]{x - 4})^3 + 4. Simplify this expression to check if it equals x.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
1m

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 f(g(x)) or g(f(x)). It requires substituting the entire expression of one function into the variable of the other, allowing us to analyze how functions combine and transform inputs.
추천 영상:
4:56
Function Composition

Inverse Functions

Inverse functions reverse the effect of each other, meaning f(g(x)) = x and g(f(x)) = x for all x in the domains. Identifying inverses involves checking if composing the functions in both orders returns the original input, confirming they undo each other's operations.
추천 영상:
4:30
Graphing Logarithmic Functions

Cube Roots and Cubes

The cube root function, ∛x, and the cube function, x³, are inverse operations. Understanding how these functions interact, especially with shifts like (x - 4) or +4, is essential to correctly compose and verify if two functions are inverses.
추천 영상:
03:41
Special Products - Cube Formulas