... solution for R(r) is Rn = j0 (λr) Applying the boundary condition at r = a, we see that the eigenvalues and eigenfunctions are λn = γn , a Rn = j0 γn r , a The problem for T becomes Tn = −κ 17 85 γn ... dx for d = nπξ L for d = L , 2n L 2n The solution for u(x, t) is, 8dL2 v u(x, t) = π2c u(x, t) = v π2c ∞ n=1 ∞ n=1 n2 n(L2 cos − 4d2 n2 ) 2nπd + L sin 2nπd L sin nπξ L sin nπx sin L nπct L for ... partial differential equation, we will expand the solution in a series of eigenfunctions in x for which the coefficients are functions of t The solution for u has the form, ∞ u(x, t) = un (t) sin n=1 nπx...