1. The problem statement, all variables and given/known data I've been studying a scientific paper for my dissertation and in it there is an integral that I cannot work out how its been derived in any way shape or form, so here goes. Importantly, kθ0>>1 and θ0<<1 2. Relevant equations So the equation is ∫θθ0 θ-2e-2kθdθ (just so you know, the integral is from θ→θ0 and in the paper this apparently becomes after the integration has been performed, e-2kθθ-2/2k Yet I have no idea how this is possible, although it seems like the θ-2 has been treated as a constant. Any rules I need to use or help would be greatly appreciated.