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Plat00n
Jan16-06, 01:06 PM
I have a question on "k" of an armonic simple movement.

If we take the equation of a wave, this is:

\frac {\partial \psi (x,t)}{\partial x^2} = \frac 1 v^2 \frac {\partial^2 \psi (x,t)}{\partial t^2}

And this, if I'm not wrong, must to satisfy the independent of time Helmholtz equation:

\frac {d^2 A(x)}{dt} + k A(x) = 0

I'm ok since here?

If it's ok, the solution of the first equation could be:

\psi (x,t) = A e^{kx-wt}

Is this "k" the same that the "k" in Helmholzt equation? Is there any mistake in this?

Plat00n.

Plat00n
Jan17-06, 08:34 AM
I have a question on "k" of an armonic simple movement.
If we take the equation of a wave, this is:
\frac {\partial \psi (x,t)}{\partial x^2} = \frac 1 v^2 \frac {\partial^2 \psi (x,t)}{\partial t^2}
And this, if I'm not wrong, must to satisfy the independent of time Helmholtz equation:
\frac {d^2 A(x)}{dt} + k A(x) = 0
I'm ok since here?
If it's ok, the solution of the first equation could be:
\psi (x,t) = A e^{kx-wt}
Is this "k" the same that the "k" in Helmholzt equation? Is there any mistake in this?
Plat00n.


Nobody can help me a little?

Tom Mattson
Jan23-06, 01:55 PM
I have a question on "k" of an armonic simple movement.
If we take the equation of a wave, this is:
\frac {\partial \psi (x,t)}{\partial x^2} = \frac 1 v^2 \frac {\partial^2 \psi (x,t)}{\partial t^2}
And this, if I'm not wrong, must to satisfy the independent of time Helmholtz equation:
\frac {d^2 A(x)}{dt} + k A(x) = 0
I'm ok since here?


Not quite. It should be:

\frac {d^2 A(x)}{dx^2} + k^2 A(x) = 0


If it's ok, the solution of the first equation could be:
\psi (x,t) = A e^{kx-wt}
Is this "k" the same that the "k" in Helmholzt equation? Is there any mistake in this?


If you use the corrected version of the equation that I posted, then yes the k's are the same.