1. The problem statement, all variables and given/known data By using a suitable vector identity for ∇ × (φA), where φ(r) is a scalar field and A(r) is a vector field, show that ∇ × (φ∇φ) = 0, where φ(r) is any scalar field. 2. Relevant equations ∇×(φA) = (∇φ)×A+φ(∇×A)? 3. The attempt at a solution I honestly have no idea how to even start this one. Any help would be hugely appreciated.