"Yukawa potential" "Verify equation (1)" check((-1 / (i k - e) - 1 / (i k + e)) / (i k) == 2 / (k^2 + e^2)) "ok" "Verify equation (2)" f = m Z e^2 / (4 pi epsilon0 hbar^2) / (i k) * (exp(i k r - epsilon r) - exp(-i k r - epsilon r)) I = integral(f,r) f = 0 - eval(I,r,0) check(f == m Z e^2 / (2 pi epsilon0 hbar^2 (k^2 + epsilon^2))) "ok" Run