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Ch. 2 - Limits and Continuity
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077당신이 사용하는 게 아니라요?교과서 변경
2장, 문제 2.2.17

Calculating Limits


Find the limits in Exercises 11–22.


limx→−1/2 4x(3x+4)²

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Identify the limit expression: \( \lim_{x \to -\frac{1}{2}} 4x(3x+4)^2 \).
Substitute \( x = -\frac{1}{2} \) directly into the expression to check if it results in a determinate form.
Calculate \( 3x + 4 \) by substituting \( x = -\frac{1}{2} \), which gives \( 3(-\frac{1}{2}) + 4 = -\frac{3}{2} + 4 = \frac{5}{2} \).
Substitute \( x = -\frac{1}{2} \) into \( 4x \), which gives \( 4(-\frac{1}{2}) = -2 \).
Combine the results: \( -2 \times (\frac{5}{2})^2 \) to find the limit. Simplify the expression to complete the calculation.

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주요 개념

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

Limits

A limit is a fundamental concept in calculus that describes the behavior of a function as its input approaches a certain value. It helps in understanding how functions behave near specific points, which is crucial for defining derivatives and integrals. In this case, we are interested in the limit of the function as x approaches -1/2.
추천 영상:
05:50
One-Sided Limits

Polynomial Functions

Polynomial functions are expressions that involve variables raised to whole number powers, combined using addition, subtraction, and multiplication. The function in the limit problem, 4x(3x+4)², is a polynomial function, and understanding its structure is essential for evaluating limits. Polynomial functions are continuous everywhere, which simplifies the process of finding limits.
추천 영상:
6:04
Introduction to Polynomial Functions

Substitution Method

The substitution method is a technique used to evaluate limits by directly substituting the value that x approaches into the function, provided the function is continuous at that point. If direct substitution results in an indeterminate form, further algebraic manipulation may be necessary. In this case, substituting x = -1/2 into the polynomial will help find the limit.
추천 영상:
04:27
Substitution With an Extra Variable