nepomukk

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2 years, 219 days

MaplePrimes Activity


These are replies submitted by nepomukk

That´s complex but helpful, thanks!

@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

 
 
 

@Rouben Rostamian  

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!

@Rouben Rostamian  

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

Hello,

Thank you for the help and tips. I'll get on quite well with that.
To your questions:
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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