/*! 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} Q4P Change the independent variable ... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Change the independent variable to simplify the Euler equation, and then find a first integral of it.

4.∫x1x2yy'2+y2dx

Short Answer

Expert verified

Answer

The first integral of the Euler equation is x'=Cyy2-C2.

Step by step solution

01

Given Information

The given integral is∫x1x2yy'2+y2dx.

02

Definition of Euler equation    

For the integralI(ε)=F∫x1x2(x,y,y')dx, the Euler equation is mathematically presented as ddxdFdy'-dFdy=0.

03

Find the Euler equation of the given function


The given integral is ∫x1x2yy'2+y2dx.

First, let’s change the variables as follows:

∂F∂x'=x'y31+x'2y2∂F∂x=0

By using the two equations above, we can rewrite the integral.

∫yy2+y'2dx=∫yy2+y'2x'dy=∫yy2+x'-2x'dy=∫x'2y2+1dy

Let Fx,y,y'=yx'2y2+1.

By the definition of the Euler equation,ddy∂F∂x'-Ï€¹ó∂x=0.

Differentiate F with respect to x' and x.

∂F∂x'=x'y31+x'2y2∂F∂x=0

The Euler becomes as shown below.

ddxx'y31+x'2y2=0x'y31+x'2y2=C

The differential equation is x'=Cyy4-C2

Therefore, the first integral of the Euler equation is x'=Cyy4-C2

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Find the Lagrangian and the Lagrange equation for the pendulum shown. The vertical circle is fixed. The string winds up or unwinds as the massswings back and forth. Assume that the unwound part of the string at any time is in a straight-line tangent to the circle. Letbe the length of the unwound string when the pendulum hangs straight down.

In Problems 5 to 7, use Fermat’s principle to find the path followed by a light ray if the index of refraction is proportional to the given function.

(y-1)-12

A simple pendulum (Problem 4) is suspended from a mass Mwhich is free to movewithout friction along the xaxis. The pendulum swings in thexyplane and gravityacts in the negativezdirection. Find the Lagrangian and Lagrange’s equations forthe system.

A hoop of mass m in a vertical plane rests on a frictionless table. A thread is wound many times around the circumference of the hoop. The free end of the thread extends from the bottom of the hoop along the table, passes over a pulley (assumed weightless), and then hangs straight down with a mass m (equal to the mass of the hoop) attached to the end of the thread. Let xbe the length of thread between the bottom of the hoop and the pulley, letybe the length of thread between the pulley and the hanging mass, and letθbe the angle of rotation of the hoop about its center if the thread unwinds. What is the relation betweenx,y, andθ? Find the Lagrangian and Lagrange’s equations for the system. If the system starts from rest, how does the hoop move?

Write theθLagrange equation for a particle moving in a plane ifV=V(r) (that

is, a central force). Use theθequation to show that:

(a) The angular momentum r×mvis constant.

(b) The vector r sweeps out equal areas in equal times (Kepler’s second law).

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.