6760, Math 21a, Fall 2009

Exhibits page Math 21a 2009, Multivariable Calculus

Triple Cross product

Course head: Oliver Knill

Office: SciCtr 434

Email: knill@math.harvard.edu

In a homework problem, you had to verify the identity
a x (b x c) = (a.c)b - (a.b) cHere is how you could verify that fast with Mathematica u = {u1, u2, u3}; v = {v1, v2, v3}; w = {w1, w2, w3}; Simplify[ Cross[u, Cross[v, w]] == (u.w) v - (u.v) w ]You can not throw this into wolfram alpha yet to get an answer, but if you copy paste that into Mathematica you should get an answer. You do not have to remember the above identity. |

Questions and comments to knill@math.harvard.edu

Math21b | Math 21a | Fall 2009 |
Department of Mathematics |
Faculty of Art and Sciences |
Harvard University