/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 11 Find the orthogonal trajectories... [FREE SOLUTION] | 91Ó°ÊÓ

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Find the orthogonal trajectories of the family of ellipses having center at the origin, a focus at the point \((c, 0)\), and semimajor axis of length \(2 c\).

Short Answer

Expert verified
The orthogonal trajectories of the family of ellipses with center at the origin, a focus at the point \((c, 0)\), and semimajor axis of length \(2c\) is given by the equation: \[y^4 = 8x^4\]

Step by step solution

01

Find the equation of the family of ellipses

To find the equation for the given family of ellipses, we will use the general equation of an ellipse centered at the origin: \[\frac{x^2}{a^2}+\frac{y^2}{b^2}=1\] Since the semimajor axis has a length of \(2c\), we have \(a = 2c\). To find the length of semiminor axis \(b\), we will use the distance between the center of the ellipse and a focus, which is \(c\). The relationship between \(a\), \(b\), and \(c\) is given by the following equation: \[c^2 = a^2 - b^2\] Substitute \(a = 2c\) into the equation: \[c^2 = (2c)^2 - b^2\] Solve for \(b\): \[b^2 = (2c)^2 - c^2 = 3c^2\] Now, we have the equation of the family of ellipses: \[\frac{x^2}{(2c)^2}+\frac{y^2}{3c^2}=1\]
02

Differentiate the equation

Next, we will differentiate the equation with respect to \(x\) using implicit differentiation. The derivative is denoted as \(\frac{dy}{dx}\). Differentiate both sides while treating \(c\) as a constant: \[\frac{2x}{(2c)^2} \cdot \frac{dx}{dx} + \frac{2y}{3c^2} \cdot \frac{dy}{dx} = 0\] Simplify the equation and solve for \(\frac{dy}{dx}\): \[\frac{dy}{dx} = -\frac{2x}{y}\]
03

Replace the derivative with its negative reciprocal

To find the orthogonal trajectories, we will replace \(\frac{dy}{dx}\) with its negative reciprocal, \(-\frac{y}{2x}\): \[-\frac{y}{2x} = -\frac{2x}{y}\]
04

Solve the new equation for \(y\)

Now, we will solve the new equation for \(y\): \[\frac{y^2}{2x} = \frac{4x^3}{y^2}\] Multiply both sides by \(y^2\): \[y^4 = 8x^4\]
05

Write the final equation

The final equation for the orthogonal trajectories is: \[y^4 = 8x^4\] This equation represents the orthogonal trajectories of the family of ellipses with center at the origin, a focus at the point \((c, 0)\), and semimajor axis of length \(2c\).

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