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.
∇×(φA) = (∇φ)×A+φ(∇×A)?
The Attempt at a Solution
I honestly have no idea how to even start this one. Any help would be hugely appreciated.