Help with interpretation of question. (Differential equations)

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The discussion focuses on solving a differential equation related to a linear oscillator using the substitution \( x = e^{rx} \). The derived solution is \( x(t) = c_1 e^{t(\sqrt{\gamma^2 - \omega^2})} + c_2 e^{-t(\sqrt{\gamma^2 - \omega^2})} \). The participants analyze the implications of the parameters \( \gamma \) and \( \omega \), noting that when \( \omega > \gamma \), the solution yields imaginary values, while the opposite results in real values. The constants \( c_1 \) and \( c_2 \) are determined as \( c_1 = -\frac{v}{2\omega} \) and \( c_2 = \frac{v}{2\omega} \), prompting further inquiry into their physical interpretation.

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sid9221
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http://dl.dropbox.com/u/33103477/Linear%20oscilator.png

I am having trouble understand the question, what I have done its solve the equation using the substitution x=e^{rx}

Then, I have the solution given by:

x(t)=c_1 e^{t(\sqrt{\gamma^2 - \omega^2 })} + c_2e^{-t(\sqrt{\gamma^2 - \omega^2)}}

So at x(0)=0,

c_1 + c_2 = 0

and, x'(0)=v
v=c_2(\sqrt{\gamma^2 - \omega^2} - \omega) + c_1(\sqrt{\gamma^2 - \omega^2}+\omega)

Not quite sure how to proceed as if \omega is greater than \gamma I get imaginary values and the opposite gives real, but what does that mean ?
 
Last edited by a moderator:
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Assuming everything is correct and I see it is correct up to taking the derivative and plugging in zero (I was too lazy to take the derivative). If omega > gamma, you would have e^{ait} where I am using a = radical.

What is e^{ait}\mbox{?} Can you rewrite e in this form as some other transcendental?

If they are real, you just have a DE with of the form Ae+Be.
Equal you just have a constant.

Also, I see you didn't solve for you constant. You set it up but that was it.
$$
\begin{bmatrix}1&1&0\\
\sqrt{\gamma^2-\omega^2}-\omega & \sqrt{\gamma^2-\omega^2}+\omega & v
\end{bmatrix}
$$
When you solve this system, what do you get for c_1,c_2?
 
Last edited:
Okay so working out c_1 = -v/2\omega and c_2 = v/2\omega what does that mean for the formula I don't get what I'm suppose to interpret from these results ?
 

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