Differential equations - transforming from one to another

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Homework Help Overview

The discussion revolves around two differential equations representing different physical phenomena: one describes a mass-spring-damper system, while the other pertains to an electrical circuit. The original poster seeks to transform both equations into a standard form.

Discussion Character

  • Exploratory, Problem interpretation, Assumption checking

Approaches and Questions Raised

  • The original poster expresses uncertainty about how to begin the transformation process and considers using a relationship involving natural frequency. Other participants inquire about the specific question causing difficulty and suggest methods for finding general solutions.

Discussion Status

The conversation is ongoing, with participants exploring different aspects of the problem. Some guidance has been offered regarding potential methods for solving the equations, but there is no explicit consensus on the best approach yet.

Contextual Notes

The original poster has indicated a preference to focus on part (a) of the problem for now, suggesting that part (b) may be addressed later. There is also a mention of potential confusion regarding the transformation process.

Basheesh
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Homework Statement



[tex] m\frac{d^{2}x}{dt^{2}}+c\frac{dx}{dt}+kx=F_{0}cos\omega t\\<br /> LC\frac{d^{2}V_{c}}{dt^{2}}+RC\frac{dV_{c}}{dt}+V_{c}=V_{0}cos\omega t[/tex]These two equations are for two different physical phenomena. The first is for a mass moving along an x axis. The mass is affected by a springforce k, a dampener with constant c and an outer force F(t), here set to [tex]F_0cost(\omega t)[/tex].
Explanation of the second equation follows. The gist is that they are mathematically the same (I'm translating from danish, let me know if you need the rest).

a) show that both differential equations can be brought to the form:

1:
[tex] \frac{dx^{2}}{dt^{2}}+2\alpha \frac{dx}{dt}+\omega_{0}^{2}x=fcos\omega t[/tex]

Where [tex]\alpha \geq 0[/tex] and we assume [tex]\omega > 0[/tex]

Homework Equations



1:
[tex] m\frac{d^{2}x}{dt^{2}}+c\frac{dx}{dt}+kx=F_{0}cos\omega t, LC\frac{d^{2}V_{c}}{dt^{2}}+RC\frac{dV_{c}}{dt}+V_{c}=V_{0}cos\omega t[/tex]2:
[tex] \frac{dx^{2}}{dt^{2}}+2\alpha \frac{dx}{dt}+\omega_{0}^{2}x=fcos\omega t[/tex]

The Attempt at a Solution



I'm not even sure where to start with this.
So I'm thinking that I somehow need to use:
[tex] \omega_{0}^{2} = c^2 + 4mk[/tex]

and possible take the integral of the whole thing. But I am pretty lost.
 
Last edited:
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which question are you having trouble? 1 or 2?
 
I'm having trouble with a) for now. I edited out b to avoid confusion. But I might add it later, as I think I might have trouble with that one too.
 
Use, [tex]x=Ae^{kt}+Be^{-kt}[/tex] to find the general solution and to find the particular integral [tex]x=C\cos\omega t+D\sin\omega t[/tex].
 
But how does that help me writing the two equations in the form of (1)?
 

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