Proving (∇ x A) x A = (A.∇)A-1/2∇Modulus(A power2)

[shabnam]

Homework Statement

can someone help prove this

(∇ x A) x A =(A.∇)A-1/2∇Modulus(A power2)

Homework Equations

The Attempt at a Solution

(∇ x A) x A =(A.∇)A-∇(A power2)

 

[SteamKing]

Calcululus - lu = Calculus

Have you tried expanding out both sides according to the definition of the Del operator and the cross product?

It looks like a moderately long slog thru vector algebra after that point.

 

[shabnam]

Calcululus - lu = Calculus

Have you tried expanding out both sides according to the definition of the Del operator and the cross product?

It looks like a moderately long slog thru vector algebra after that point.

Hi
Yes I did but what I achieve is the last term without factor of (1/2), don't know what to do now, what I got is (vector A power 2) and required is 1/2*(Modulus( A square)), is there any difference (A square) and Modulus(A square)