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Ch. 7 - Transcendental Functions
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077당신이 사용하는 게 아니라요?교과서 변경
7장, 문제 7.1.7

In Exercises 7–10, determine from its graph if the function is one-to-one.
f(x) = 3 - x, x < 0
= 3, x ≥ 0

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1
Understand the definition of a one-to-one function: a function is one-to-one if and only if each output value corresponds to exactly one input value. In other words, no horizontal line intersects the graph more than once.
Analyze the given piecewise function: \( f(x) = \begin{cases} 3 - x, & x < 0 \\ 3, & x \geq 0 \end{cases} \). For \( x < 0 \), the function is a line with slope \(-1\), and for \( x \geq 0 \), the function is constant at 3.
Consider the graph of the first part \( 3 - x \) for \( x < 0 \). This is a decreasing linear function, so it is one-to-one on this interval.
Look at the second part where \( f(x) = 3 \) for \( x \geq 0 \). This is a horizontal line, meaning all inputs \( x \geq 0 \) map to the same output 3, which violates the one-to-one condition on this interval.
Check if any output value is repeated for different inputs across the two pieces. Since \( f(0) = 3 \) and also \( f(x) = 3 \) for all \( x \geq 0 \), and the first piece approaches values near 3 as \( x \to 0^- \), the function is not one-to-one overall.

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이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
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주요 개념

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

One-to-One Function

A function is one-to-one (injective) if each output corresponds to exactly one input. This means no two different inputs produce the same output. Checking if a function is one-to-one helps determine if it has an inverse function.
추천 영상:
05:50
One-Sided Limits

Piecewise Functions

Piecewise functions are defined by different expressions over different parts of their domain. Understanding how each piece behaves separately and together is essential to analyze properties like continuity and injectivity.
추천 영상:
05:36
Piecewise Functions

Graphical Test for One-to-One Functions

The horizontal line test is used to determine if a function is one-to-one by checking if any horizontal line intersects the graph more than once. If it does, the function is not one-to-one.
추천 영상:
05:50
One-Sided Limits