Step by step analytical solution of temperature distribution

Fr34k
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Homework Statement


Lets say we have a 2D rectangular plate with a point heat source and some boundary conditions. I would like to solve and understand step by step the solution to this second order differential equation. Let's say dimensions of rectangular are a and b. 2 opposite sides are at a fixed temperature T1 and the other 2 are insulated. The initial temperature of the "body" is let's say T0. Our source is a δ source somewhere on the rectangular (x,y) and starts at t0. We ignore the heat dissipation due to convection and radiation. How would the temperature distribution look like T(x,y,t)? We also know the k-thermal conductivity, ρ density and c thermal diffusivity.

Homework Equations


\nabla^2T-\frac{1}{k}\frac{\delta T}{\delta t}+\frac{q(x,y,t)}{c}=0

And please don't just tell/write the solution. I would like to understand the method of solving these type of problems. I have been reading lots of books on differential equations with simpler problems or similar problems but I can not put 1 and 1 together to solve this exact situation.
I thank you all for your time in advance.
 
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The general solution I think is obtained by taking the Fourier series/transform of all variables x,y,z,t, converting into algebraic equation, solving for it and taking the inverse FS/T. You'll probably need to know the FS/T of the delta function source. The inverse FS/T is a multi-dimensional singular summation/integral where if the geometry is simple enough, you might be able to evaluate in closed form, using certain techniques. The solution obtained this way is nothing but the system's Green's function
 
Done it some time ago but I'll post what I did if someone else will have same problems.
The essential thing is to break the partial equation down into sum of components each solving a part of the whole.
one for boundary conditions + one laplace for stationary solution + one time dependant solution
The only trick here is in the stationary solution, where you have to center the system to get nicer solutions.
The rest are just known solutions to partial differential equations.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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