Differential equations time evolution

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Homework Help Overview

The discussion revolves around a differential equations problem presented in a physics context, specifically related to mechanics. Participants are exploring how to eliminate variables and derivatives to form a second-order equation.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants discuss methods to eliminate derivatives of one variable in favor of another, suggesting differentiation and substitution as potential strategies. There are questions about the appropriate methods learned by the original poster and the implications of the problem's context.

Discussion Status

The conversation includes suggestions for starting points in solving the problem, with participants offering various approaches without reaching a consensus. Some guidance has been provided regarding the differentiation of equations and the elimination of variables.

Contextual Notes

There is an emphasis on the need for clarity regarding the methods the original poster has been taught, as well as the appropriateness of posting in the correct forum for differential equations.

Katy96
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Homework Statement


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Homework Equations

The Attempt at a Solution


Any help would be appreciated
 
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katy96:
Please try to post your HW problems in the correct HW forum.

Questions about differential equations should be posted in the Calculus HW forum.

Thanks.
 
SteamKing said:
katy96:
Please try to post your HW problems in the correct HW forum.

Questions about differential equations should be posted in the Calculus HW forum.

Thanks.
It was given in a physics class as part of mechanics assignment
 
Katy96 said:
It was given in a physics class as part of mechanics assignment
It's still a calculus problem so should be posted in the relevant section.

For your question, essentially you want to eliminate every derivative of ##y## and have a DE which just involves ##x## and its time derivatives. Start by differentiating ##\frac{dx}{dt}## to obtain an equation for ##\frac{d^2 x}{dt^2}## which will leave you with 3 equations. You can use these to eliminate ##y## and its derivatives.
 
If this was given as a homework problem, surely you have been given some instruction in solving such problems. There are, in fact, several ways to solve this problem. We have no idea which method would be appropriate for you without knowing what methods you have learned. Part of the problem tells you to "Combine these to form a second order equation for x(t) and find the general solution for x(t)". Do you know how to do that?

Start by differentiating both sides of the given equation that starts "dx/dt= " with repect to t. The result will have a second order derivative of x(t) and a derivative of y(t). Use the other equation to replace that "dy/dt".
 
Or else you can obviously eliminate y between these two eqs. but then you are left with dy/dt in the result. Differentiating first eq. you get dy/dx in terms of x and derivatives and t only which you can then substitute into the other equation you just got.

Not something which requires you to be 'taught' a 'method' IMHO, just a bit of initiative or at most to be told it's possible.
 
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