1. The problem statement, all variables and given/known data Semi-infnite bar (0 < x < ∞) with unit thermal conductivity is insulated at x = 0, and is constantly heated at x = 1 over such a narrow interval that the heating may be represented by a delta function: ∂U/∂t = ∂2U/∂t2 + δ(x-1) U(x; t) is the temperature. Assume initial temperature is zero all through, and that U goes to0 as x goes to ∞, find U(x,;t) using the appropriate Fourier transform in x. 2. Relevant equations 3. The attempt at a solution Hi guys, I need help with a quick pointer - with this sort of question, how do you know which Fourier Transform to apply? (General, Sine or Cosine?) I just need help starting this one. I know as U(0,t) = 0 and that U goes to 0 as x goes to infinity and also that U(x,0) = 0 Many thanks!