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Ch. 2 - Limits
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243당신이 사용하는 게 아니라요?교과서 변경
2장, 문제 2.6.17

Determine whether the following functions are continuous at a. Use the continuity checklist to justify your answer. 
f(x)=2x^2+3x+1 / x^2+5x; a=−5

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1
Identify the function: \( f(x) = \frac{2x^2 + 3x + 1}{x^2 + 5x} \).
Check if \( f(x) \) is defined at \( x = -5 \). Substitute \( x = -5 \) into the denominator: \( (-5)^2 + 5(-5) = 25 - 25 = 0 \). The function is not defined at \( x = -5 \) because the denominator is zero.
Since \( f(x) \) is not defined at \( x = -5 \), it is not continuous at \( x = -5 \).
For a function to be continuous at a point \( a \), it must be defined at \( a \), the limit as \( x \) approaches \( a \) must exist, and the limit must equal \( f(a) \).
Since \( f(x) \) is not defined at \( x = -5 \), it fails the first condition of the continuity checklist, confirming it is not continuous at \( x = -5 \).

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주요 개념

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

Continuity of Functions

A function is continuous at a point 'a' if three conditions are met: the function is defined at 'a', the limit of the function as 'x' approaches 'a' exists, and the limit equals the function's value at 'a'. This concept is fundamental in calculus as it ensures that there are no breaks, jumps, or holes in the graph of the function at that point.
추천 영상:
05:34
Intro to Continuity

Limit of a Function

The limit of a function describes the behavior of the function as the input approaches a certain value. For continuity, it is essential to evaluate the limit from both the left and right sides of 'a'. If both limits agree and equal the function's value at 'a', the function is continuous at that point.
추천 영상:
06:11
Limits of Rational Functions: Denominator = 0

Rational Functions

Rational functions are ratios of polynomials, and their continuity can be affected by points where the denominator equals zero. In this case, we must check if the function is defined at 'a' and if the limit exists. If the denominator is zero at 'a', the function is not continuous there, necessitating careful analysis of the function's behavior around that point.
추천 영상:
6:04
Intro to Rational Functions