Question

The curl of curl of a vector is given by,

(a) Div(Grad V) – (Del)^2V

(b) Grad(Div V) – (Del)^2V

(c) (Del)^2V – Div(Grad V)

(d) (Del)^2V – Grad(Div V)

This question was addressed to me in an internship interview.

My enquiry is from Vector Calculus in portion Vector Calculus of Electromagnetic Theory

Answer 1

Correct answer is (b) Grad(Div V) – (Del)^2V

Easiest explanation: Curl (Curl V) = Grad (Div V) – (Del)^2V is a standard result of the curl operation.