Difficult partial differential Problem

2 replies · 2K views · last reply
big dream
Problem:
$${\frac {\partial }{\partial t}}A\left( y,t \right) +6\,\Lambda\,\Omega\, \left( {y}^{2}-y \right) \sin \left( t \right) ={\frac {\partial ^{2}}{\partial {y}^{2}}}A \left( y,t \right)$$
$${\frac{\partial }{\partial y}}A \left( t,0 \right) ={\frac {\partial }{\partial y}}A \left( t,1 \right) =0$$
Boundary condition
$${\frac{\partial }{\partial y}}A \left( t,0 \right) ={\frac {\partial }{\partial y}}A \left( t,1 \right) =0$$
ANSWER OF THIS EQUATION IS
$$A \left( y,t \right) =6\,\Lambda\, \left( \Im \right) \, \left\{ [{\frac {i\sinh \left( \alpha\,y \right) }{\alpha}}-{\frac {i \left( 1-\cosh \left( \alpha \right) \right) \cosh \left( \alpha\,y \right) }{\alpha\,\sinh \left( \alpha \right) }}+i{y}^{2}-iy+2\,{\Omega}^{-1}]{{\rm e}^{it}} \right\}$$
Where, $$\alpha=1/2\, \left( 1+i \right) \sqrt {2}\sqrt {\Omega}$$
attempt at a solution

Maple didn't give an answer. I don't know how to get this kind of solution.
Handwritten derivation of a PDE solution: Omega dA/dt + 6 Lambda Omega (y^2 - y) sin t = d^2A/dy^2, boundary conditions, ansatz A = Im(q(y)e^{it}), and the relation F = E (1 - cosh a)/sinh a.
 
Attachments
  • Handwritten derivation of a PDE solution: Omega dA/dt + 6 Lambda Omega (y^2 - y) sin t = d^2A/dy^2, boundary conditions, ansatz A = Im(q(y)e^{it}), and the relation F = E (1 - cosh a)/sinh a.
    IMG_20171223_030037.jpg
    28.3 KB · Views: 734
  • Like
Likes   Reactions: Delta2
This is a diffusion equation with some periodic source term. You should try separation of variables for this. There is an example on the wiki page, but searching for separation of variables of nonhomogeneous heat equation will lead to many extensive examples.
You could start here:
https://en.wikipedia.org/wiki/Separation_of_variables#Example:_nonhomogeneous_case
http://www.math.psu.edu/wysocki/M412/Notes412_10.pdf
 
  • Like
Likes   Reactions: BvU