- #1

Muthumanimaran

- 81

- 2

## Homework Statement

This is not a homework problem, I am currently reading the Derivation of potential of a charged particle in Electric and Magnetic field from the book Mechanics by Symon (I attached the image of the page), I need to know how to expand the vector cross product

such as $$\vec{v}\times({\nabla}{\times}\vec{A})=?$$

## Homework Equations

ax(bxc)=(a.c)b-(a.b)c (Lagrange's formula)

## The Attempt at a Solution

I tried to expand the vector triple product using Lagrange's formula, but what i am getting is,

$$(\vec{v}.\vec{A})\nabla-(\nabla.\vec{A})\vec{v}$$

As far as I know $$(\nabla.\vec{A})\vec{v}\neq(\vec{v}.\nabla\vec{A})$$ Is there any mistake I did during my calculation or should I use some other formula? please help.