Recent content by maddogtheman

  1. M

    Solving Laplace's equation in an annulus

    Ok I think I realized my problem. My tutorial solved a slightly different DE for R(r) which resulted in the diffence of powers. Also for this problem I think the n=0 case takes on the solution A_0 + B_0*ln(r) which would give a final solution u(r,theta)=3+2ln(r)/ln(2). I'm going to bed, let me...
  2. M

    Solving Laplace's equation in an annulus

    u(r,\vartheta) = A_0 + B_0 right?
  3. M

    Solving Laplace's equation in an annulus

    Well n=0 has to be one right? I can't think of any others
  4. M

    Solving Laplace's equation in an annulus

    Yeah I think you're right for some reason the -n-1 power is used in our class tutorial. Yes I understand how it was found and the principal of linear superposition. The second part of the expression is a constant because u is theta independent for the first set of boundary conditions.
  5. M

    Solving Laplace's equation in an annulus

    Yeah I have and I think that leave's me with u(r,\vartheta) = \sum_{n=0}^\infty (A_n r^n + B_n r^{-n-1})(C_n cos(n\vartheta) + D_n sin(n\vartheta)) but I don't know how to apply the boundary conditions correctly
  6. M

    Solving Laplace's equation in an annulus

    Homework Statement Solve Laplace's equation \nabla^2 u(r,\vartheta) =0 in an annulus with inner radius r_1 and outer radius r_2 . (a) For boundary conditions take u(1,\vartheta) = 3 and u(2,\vartheta) = 5. (b) What is the solution using this second set of boundary conditions...
  7. M

    Exploring Bessel Function Generating Function

    Thanks can't believe I missed it
  8. M

    Exploring Bessel Function Generating Function

    Homework Statement The Bessel function generating function is e^{\frac{t}{2}(z-\frac{1}{z})} = \sum_{n=-\infty}^\infty J_n(t)z^n Show J_n(t) = \frac{1}{\pi} \int_0^\pi cos(tsin(\vartheta)-n\vartheta)d\vartheta Homework Equations The Attempt at a Solution So far I...
  9. M

    Proving Hermitian if it has real eigenvalues

    I assumed the basis to be orthogonal but I think it makes for a rigorous proof.
  10. M

    Proving Hermitian if it has real eigenvalues

    If you had an operator A-hat whose eigenvectors form a complete basis for the Hilbert space has only real eigenvalue how would you prove that is was Hermitian?
  11. M

    Find d/dx in terms of d/d(theta)

    If x=cos(theta) how do you find what d/dx is in terms of d/d(theta)?
  12. M

    Solve 4th Order Differential Equations (No Guesswork!)

    [SOLVED] Forth Order DiffEq I've recently come across the following differential equations. y''''+y=0 and y''''-y=0. Can differential equations such as these be solved with any technique other than guessing for the particular solutions? They seem very simular to trig's equation but are still...
  13. M

    Fourier series technique to show that the following series sum to the quantities

    Use the Fourier series technique to show that the following series sum to the quantities shown: 1+1/3^2+1/5^2+...+1/n^2=pi^2/8 for n going to infinity I foudn the series to be: sum(1/(2n-1)^2,n,1,infinity) but I don't know how to prove the idenity. I don't know how to go about...
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