Solve the diffusion-convection problem:
u - uxx + ux = 0, x ∈ R, t > 0
ux,0 = fx, lim ux,t = 0
u(x,t) = ∫ dz, where a = -∞ and b = ∞. Use z as the integration variable. "∞" is available as a constant in this context. Please try both forms of convolution, keeping in mind that convolution is commutative.