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Ch.12 - Parametric and Polar Curves
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243당신이 사용하는 게 아니라요?교과서 변경
12장, 문제 12.4.51d

Explain why or why not Determine whether the following statements are true and give an explanation or counterexample.
d. The point on a parabola closest to the focus is the vertex.

검증된 단계별 안내
1
Recall the definition of a parabola: it is the set of all points equidistant from a fixed point called the focus and a fixed line called the directrix.
Understand that the vertex of the parabola is the point on the parabola that lies exactly halfway between the focus and the directrix.
To determine if the vertex is the closest point on the parabola to the focus, consider the distance from any point on the parabola to the focus and compare it to the distance from the vertex to the focus.
Use the geometric property that the distance from the vertex to the focus is the shortest distance from the parabola to the focus because the vertex lies on the axis of symmetry and minimizes this distance.
Conclude that the vertex is indeed the point on the parabola closest to the focus, since any other point on the parabola will be farther away due to the parabola's shape and definition.

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이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
4m
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주요 개념

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

Definition of a Parabola and Its Focus

A parabola is the set of all points equidistant from a fixed point called the focus and a fixed line called the directrix. The vertex is the point on the parabola closest to the directrix and lies midway between the focus and directrix.
추천 영상:
가이드 코스
05:43
Definition of the Definite Integral

Distance from a Point to the Focus

The distance from any point on the parabola to the focus varies along the curve. Understanding how this distance changes is essential to determine which point on the parabola is closest to the focus.
추천 영상:
6:58
Convert Points from Rectangular to Polar

Optimization and Minimizing Distance

To find the point on the parabola closest to the focus, one must analyze the distance function and use calculus techniques like differentiation to find its minimum value, confirming whether the vertex is indeed the closest point.
추천 영상:
09:07
Example 1: Minimizing Surface Area