What is the cross product of [2, 5, 4][2,5,4] and [1, -4, 0] [1,4,0]?

2 Answers
Mar 4, 2017

[16,4,-13].[16,4,13].

Explanation:

[2,5,4]xx[1,-4,0]=|(i,j,k),(2,5,4),(1,-4,0)|,

=16i+4j-13k,

=[16,4,-13].

Mar 4, 2017

The vector is =〈16,4,-13〉

Explanation:

The vector perpendicular to 2 vectors is calculated with the determinant (cross product)

| (veci,vecj,veck), (d,e,f), (g,h,i) |

where 〈d,e,f〉 and 〈g,h,i〉 are the 2 vectors

Here, we have veca=〈2,5,4〉 and vecb=〈1,-4,0〉

Therefore,

| (veci,vecj,veck), (2,5,4), (1,-4,0) |

=veci| (5,4), (-4,0) | -vecj| (2,4), (1,0) | +veck| (2,5), (1,-4) |

=veci(16)-vecj(-4)+veck(-13)

=〈16,4,-13〉=vecc

Verification by doing 2 dot products

veca.vecc

=〈2,5,4>.〈16,4,-13〉=32+20-52=0

vecb.vecc

=〈1,-4,0〉.〈16,4,-13〉=16-16+0=0

So,

vecc is perpendicular to veca and vecb