1. The problem statement, all variables and given/known data The problem and its solution are attached in TheProblemAndSolution.jpg. 2. Relevant equations Stoke's theorem: ∮_C F ⋅ dr = ∮_C (F ⋅ T^) dS = ∫∫_S (curl F) ⋅ n^ dS 3. The attempt at a solution In the solution attached in the TheProblemAndSolution.jpg file, I don't understand what's going on with the integral that has |n^ ⋅ k^| on a denominator. Could someone please add the steps that are skipped by the solution?