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Ch. 9 - Differential Equations
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243당신이 사용하는 게 아니라요?교과서 변경
9장, 문제 9.3.45

Orthogonal trajectories Use the method in Exercise 44 to find the orthogonal trajectories for the family of circles x² + y² = a²

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1
Start with the given family of circles: \(x^{2} + y^{2} = a^{2}\), where \(a\) is a parameter representing the radius of each circle.
Differentiate both sides of the equation implicitly with respect to \(x\) to find the slope of the tangent to the circles. This gives: \(2x + 2y \frac{dy}{dx} = 0\).
Solve for \(\frac{dy}{dx}\) to find the slope of the tangent lines to the circles: \(\frac{dy}{dx} = -\frac{x}{y}\).
Since orthogonal trajectories intersect the original family at right angles, their slopes are negative reciprocals. Therefore, the slope of the orthogonal trajectories satisfies \(\frac{dy}{dx} = \frac{y}{x}\).
Set up the differential equation \(\frac{dy}{dx} = \frac{y}{x}\) and solve it by separating variables or using an appropriate method to find the family of orthogonal trajectories.

비슷한 문제에 대한 검증된 영상 답변:

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.

Orthogonal Trajectories

Orthogonal trajectories are curves that intersect a given family of curves at right angles (90 degrees). To find them, one typically derives a differential equation for the original family and then finds a new family whose slopes are negative reciprocals, ensuring perpendicularity.

Differential Equations of Families of Curves

A family of curves defined by an equation with a parameter can be expressed as a differential equation by differentiating with respect to x and eliminating the parameter. This differential equation characterizes the slope of the tangent lines to the curves in the family.
추천 영상:
04:00
Solutions to Basic Differential Equations

Slopes and Negative Reciprocal Relationship

For two curves to be orthogonal at their intersection, the product of their slopes must be -1. This means if the slope of the original family is dy/dx = m, the slope of the orthogonal trajectories is dy/dx = -1/m, which is used to find the differential equation of the orthogonal trajectories.
추천 영상:
05:45
Understanding Slope Fields