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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 58a

Solve each problem. See Example 4. Suppose that the cost of mailing a letter weighing x ounces, where x>0, is ƒ(x)=55-15[[1-x]]cents. What is the cost of mailing a 2.6-ounce letter?

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1
First, understand the function given: \(f(x) = 55 - 15 \times \lceil 1 - x \rceil\), where \(\lceil \cdot \rceil\) denotes the ceiling function, which rounds a number up to the nearest integer.
Identify the value of \(x\) for the problem: here, \(x = 2.6\) ounces, which is the weight of the letter.
Calculate the expression inside the ceiling function: compute \(1 - x\), so \(1 - 2.6\).
Apply the ceiling function to the result from the previous step: find \(\lceil 1 - 2.6 \rceil\).
Substitute the value of the ceiling function back into the original function \(f(x)\) and simplify to find the cost of mailing the 2.6-ounce letter.

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주요 개념

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

Piecewise and Step Functions

Step functions assign constant values over intervals and often involve the greatest integer (floor) function. Understanding how these functions behave, especially with the floor function, is essential to evaluate expressions like ƒ(x) = 55 - 15⌊1 - x⌋ correctly.
추천 영상:
4:07
Decomposition of Functions

Greatest Integer (Floor) Function

The floor function, denoted ⌊x⌋, returns the greatest integer less than or equal to x. It is crucial to correctly compute ⌊1 - x⌋ for a given x, as it affects the value of the cost function in the problem.
추천 영상:
6:04
Intro to Rational Functions

Function Evaluation

Evaluating a function means substituting the given input value into the function's formula and simplifying. Here, substituting x = 2.6 into ƒ(x) requires careful calculation of the floor term and arithmetic to find the mailing cost.
추천 영상:
4:26
Evaluating Composed Functions