Solving Diffusion Equation with Boundary Conditions

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The discussion focuses on solving the diffusion equation with specific boundary conditions. The user is seeking guidance on where to begin, expressing uncertainty about the necessary study materials. They reference two textbooks, Riley's "Mathematical Methods for Physics and Engineering" and Zill's "Advanced Engineering Mathematics," asking for specific chapters or topics to review. A response highlights the importance of clearly stating the diffusion equation and questions the inclusion of an unspecified variable "n" in the boundary conditions. The conversation emphasizes the need for clarity in problem statements to facilitate effective assistance.
tirwit
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Homework Statement


Obtain the solution of the diffusion equation, u(t,x)

a) satisfying the boundary conditions:
u(t,0)=u1, u(t,l)=u2, u(0,x)=u1+(u2-u1)x/l+a.sin(n\pix/l);

b) in the semi-plane x > 0, with u(t,0)=u0+a.sin(\omegat).

Homework Equations


Wish I knew...


The Attempt at a Solution


I haven't done none because I don't know where to start. I just want to ask what should I study to solve this problem. I have Riley's "Mathematical Methods for Physics and Engineering" and Zill's "Advanced Engineering Mathematics". If you have and can point me out the chapters, I would be much appreciated, or you can just tell me the subjects, that I'll try and look for them in the books.
 
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tirwit said:

Homework Statement


Obtain the solution of the diffusion equation, u(t,x)

It is good form to give the diffusion equation in case anyone that might help you doesn't remember it exactly and doesn't have their PDE book handy.

a) satisfying the boundary conditions:
u(t,0)=u1, u(t,l)=u2, u(0,x)=u1+(u2-u1)x/l+a.sin(n\pix/l);

That last equation looks strange. What is n? There is usually no "n" in the BC. Are you sure you have stated the original problem correctly?
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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