1. The problem statement, all variables and given/known data The problem states that it is required to prove that ∇f(r)=f'(r)R/r where r is the vector field 2. Relevant equations ∇=(∂/∂x)i + (∂/∂y)j + (∂/∂z)k R= xi + yj +zk r = √(x^2+y^2+z^2) 3. The attempt at a solution The trouble that I am having with this problem is the inability to truly comprehend what f(r) truly means⋅ Is f(r) dependent on the vector field R???