1. The problem statement, all variables and given/known data The problem is given in the following photo: Actually I did the first proof but I couldn't get the second relation. (Divergence of E cross H). 2. Relevant equations They are all given in the photo. (a) (b) and (c). 3. The attempt at a solution What I tried is to interchange divergence and cross products as it was given in (a). But I couldn't figure out how I am going to get 2 terms at the end. I also tried to apply the relation in (c), but it does not have any cross product, and I think there is no way to use equation in (b). So how can I prove the equation given at the end by using (a) (b) or (c) without decomposing into components or using Einsteins notation.