15 Reputation

2 years, 277 days

Perfect!...

@Rouben Rostamian

Perfect. Many many thanks. This has brought me a lot further. I would still have a little question ...

How can I get the expression:

`sin(k1*(c*t-x))`

change to these:

`-sin(k1*(x-c*t)) `
Thanks again!

fg

New problem description...

Thank you for the quick response and sorry for the unclear description.

I try to describe my problem again.

The approach function

`u := a(x)*sin(k1*(-c*t+x))`

is used in the following pde:

`pde := diff(u(x, t), t, t)-c^2*(diff(u(x, t), x, x));`

That is, I have simply formed the appropriate derivatives. The goal later is to determine the variable a(x). I would like to control this "hand calculation". With "pdsolve" I have the problem to integrate the approach function "u" correctly with. "pdetest" is a good suggestion as a last step for comparison. But how do I get here?

Many many thanks again!

Way to solution...

Many thanks for the help!
We now come to the following solution:

`-c^2*(d^2*a*sin(k1*(-c*t+x))/dx^2+2*d*a*k1*cos(k1*(-c*t+x))/dx)`

which intermediate steps would I have to insert this in maple yet? Since I have to check several approach functions, I want to "automate" the control as much as possible.

Thanks a lot!

Frank

Started successfully...

Hello,

Thank you for the help and tips. I'll get on quite well with that.
kf1, A1 etc. are constant variables (wavenumber, amplitudes ...)
In my case, the sulution assumption ends with
u
(3). The equation could, however, be extended at desired, higher non-linearities.

How exactly do I deal with the constant variables in my case?
Do I value these in advance?

Thanks a lot!

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