## 6 Badges

5 years, 156 days

## @Preben Alsholm    There is ...

There is a physical meaning for the relation between C1 nad B in Mechanics. I do know that 'dsolve' works for differential equations, however, the desire result could be derived by it!

## @tomleslie  I meant why it was ok ...

I meant why it was ok and done in your computer but not in my laptop. How did you edit the file? For example: alpha1 was changed to alpha[1]...
Did you write the whole file again?

## @tomleslie    Hello, yes it&...

Hello, yes it's ok now. It's ambiguous yet.. What have happened?

## @Kitonum    Thanks. But it d...

Thanks. But it doesn't work for me.... It drove me crazy!!! It workes correctly last week. I had to get some results by the file today...

## @tomleslie    Great, God ble...

Great, God bless you and happy new year.

## @tomleslie    What a simple ...

What a simple solution!

Thanks.

## @_Maxim_ The integral term in F2(r)...

@_Maxim_

The integral term in F2(r) must be a value necessarily as long as those two Nu are close toghether. Indeed in the loop I want this expression " Error= (Nu_final- Nu_guess)<1e-3" to be satisfied and then the loop is going to be interrupted.

The program is correct in the first iteration for \phi= 0.06 and "initial guess Nu=3.6941" and the "final calculated Nu= 3.6942". I already know the Final Nu for \phi= 0.06!!!! But for other values of \phi I could not get any solution precisely.

## @_Maxim_   By the way, it does no...

@_Maxim_

By the way, it does not matter whether or not k is zero @﻿ initial guess "For The First Time", the first iteration in a potential loop. As you know the initial guess for Nu is just for calculation of the integral and after that I removed it by this command: Nu:= 'Nu'.

The only important thing is this fact that the final calculated for Nu, in the end of the loop, must be equal to the initial guess.

## @_Maxim_  Hello, thanks for yo...

Hello, thanks for your consideration dear.

Yes, I want to find the Nu if the determinat is equal zero. And the problem is exactly here that the at the initial guess the determinant, k, might be any number, not necessarily zero. That is why I want to correct the Nu by replacing the initial guess with the final calculated Nu. It assumed to be difficult for me.

## @vv  Thanks. But r is not equa...

Thanks. I must change the domain then! That's 3.195986267 if

0.2 <r< 1

Thanks again.

## @Markiyan Hirnyk  Thanks dear,...

Thanks dear,

Yes you're right. I solve that system in Matlab (written below) and those solutions are the same.

[ 1.6759649064951345004378236436225, 0.7729562969870007822477027324705, 1.9940322524732747423780039106827]

By the way, I wrote some indices wrongly in my question!!! Now I corrected it and we can see this is true as well.

 (1)

 (2)

Download Edited_Solve_Equation.mw

Best.

## How solve this PDE...

@tomleslie

I thank you for your comments and answering to my question.

Unfortunately I didn't write the fourth boundary conditions for you.
The four boundary conditions are in here:

V(r1,z)= V(r2,z)=0
V(r,0)= V(r,b)=0

and this point that the coordinates are

r1 < r <r2   &    0< z < b

And I want to tell you I don't have the Matlab Code I just olnly the final solution attached in the Maple primes websie.

## @Carl Love    Thanks a lot Mr....

Thanks a lot Mr. Carl.

God bless you

## @tomleslie    Ok, thanks. But ...

Ok, thanks. But I thought Maple could give the right answer instead of  F_1(x+t)+ F_2(t-x)+ cos(x).

Is the answer correct???

Unfortunately, I could not solve it analytically, so it was not possible to me to compare the numerical and Exact solutions too!!!

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