How to Solve Complex Temperature Distribution Problems Involving Heated Spheres?

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The discussion focuses on solving complex temperature distribution problems involving two heated spheres. Participants express confusion about the derivation of infinite equations related to the temperature distribution and the proper formulation of the summation limits. A suggestion is made to truncate the infinite set into a finite number of equations for practical computation. The conversation emphasizes the importance of accurately defining the equations and the variables involved, particularly the role of the summation limits and the indices. Clarification is sought on the formulation and the implications of the derived equations for specific values of R and N.
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I don't know where to start and where and i do not understand the problem could you help me out please

In solving for the temperature distribution resulting from two spheres separated by distance and heated to maintain their temperatures equal to unity one derives the following set of infinite equations in coefficients

An + sigma [( Ap*(-1)^ n+p * (n+p)!/n!p! * (R)^-n-p-1] = Sn0

sigma is over the limit p=0 to p=infinity , n=0,1,2,..

where Sno is equal to unity if , and zero otherwise. This infinite set can be truncated to a set of finite equations (N) in the same number of unknowns by considering only the equations and unknowns with n<N . Write a computer program that will solve An for a given value of R and N . Take R=2 and vary N from 2 to 20 and plot the results for Ao. Next, take N=20 and plot Ao versus R as R is varied from 2 to 8. Show the prediction of the following approximate formula:
Ao= 1/(1+R^-1 + R^-4)
 
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you need to copy the problem more accurately:

sigma is over the limit p=0 to p=infinity , n=0,1,2,..

THe usage of limit here is incorrect. I'd write: The summation is over the range p=0 to p=infinity.

the n=0,1,2,... isn't part of the summation. you get one equation with n=0, another with n=1 etc.

where Sno is equal to unity if , and zero otherwise.

What is this?


if you can't see what is going on, try to write out a few of the equations for n=0, 1,2
 
I tried to combine those 2 formulas but it didn't work. I tried using another case where there are 2 red balls and 2 blue balls only so when combining the formula I got ##\frac{(4-1)!}{2!2!}=\frac{3}{2}## which does not make sense. Is there any formula to calculate cyclic permutation of identical objects or I have to do it by listing all the possibilities? Thanks
Since ##px^9+q## is the factor, then ##x^9=\frac{-q}{p}## will be one of the roots. Let ##f(x)=27x^{18}+bx^9+70##, then: $$27\left(\frac{-q}{p}\right)^2+b\left(\frac{-q}{p}\right)+70=0$$ $$b=27 \frac{q}{p}+70 \frac{p}{q}$$ $$b=\frac{27q^2+70p^2}{pq}$$ From this expression, it looks like there is no greatest value of ##b## because increasing the value of ##p## and ##q## will also increase the value of ##b##. How to find the greatest value of ##b##? Thanks
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