I have this differential equation.
$$Dc''+H=0 $$
where the partial of the concentration is with respect to z the distance. H is the rate per unit volume of particles generated and D is the diffusion constant.
I have gone completely brain dead on it.
I tried just treating it an an ordinary ODE and using direct integration but that doesn't seem to work. I also tried using Fourier transforms of derivatives but I cant obtain the inverse Fourier transform at the end because my problem is only valid for z