1. The problem statement, all variables and given/known data I need to give scattering amplitude f(θ) in Born approximation to the first order in the case of delta function scattering potential δ(r). The problem is in spherical coordinate and I'll give major equation concerned. 2. Relevant equations The equation for scattering amplitude is given by f(θ) = C ∫_0^∞ dr rV(r)sinqr where q is only a function of θ, so treat it as a constant in this formula, and C is just another constant, too. The only issue left is to insert the delta function into the formula, and this is exactly the problem: no equation can be used in such case where the integral range begin just at zero. 3. The attempt at a solution I look every textbook to find useful formulas, found nothing. And I tried to create a new function such that the integral range is from -∞ to ∞, then half the new integral to obtain a result, but it achieved nothing since it gives zero, so help me, please!