# triple cross product

## Primary tabs

Defines:
Lagrange's formula
Synonym:
vector triple product, triple vector product
Type of Math Object:
Definition
Major Section:
Reference
Parent:
Groups audience:

## Mathematics Subject Classification

### triple cross product

The expansion formula agrees with a simple nemotechnic rule:
"exterior dot far times near minus exterior dot near times far".
That rule works if $\vec{a}$ is in left or right side.

### Re: triple cross product

Thank you, it is a good mnemonic -- I think I add it to the object, if you give permission!
Jussi

### Re: triple cross product

Dear Mr. pahio,
Of course yes!! For me is an honor.
Best regards,
Pedro

### triple vector cross product

Hi, It would be nice to have some geometric proof of this for offering some insight.

### "geometric proof"

See http://it.wikipedia.org/wiki/Prodotto_misto (Semplificazioni) and http://es.wikipedia.org/wiki/Doble_producto_vectorial (Demostración).