Re: *newbie* output of ScalarTripleProduct
- To: mathgroup at smc.vnet.net
- Subject: [mg106785] Re: *newbie* output of ScalarTripleProduct
- From: Szabolcs Horvát <szhorvat at gmail.com>
- Date: Sat, 23 Jan 2010 07:34:35 -0500 (EST)
- References: <hjbvbk$2st$1@smc.vnet.net>
On 2010.01.22. 11:40, pippo wrote:
> I'm (almost) new to mathematica ...
> I coped this from some tutorial ...
>
> Needs["VectorAnalysis`"]
> r1 = {1, -3, 2}
> r2 = {3, 7,-5}
> r3 = {4, 1, 6}
> r={x,y,z}
> ScalarTripleProduct[r-r1,r2-r2,r3-r1]==0
>
> the output i get is:
> Out[6]= True
>
> :-(
>
> What am I missing ?
>
It means that the result of ScalarTripleProduct[r-r1,r2-r2,r3-r1] is 0,
and 0 == 0 is of course True. You have r2-r2 == {0,0,0} in the product
(probably a typo).
Szabolcs