- #1
Roodles01
- 128
- 0
Homework Statement
Still having a little trouble so here's the problem.
(ex + ez) x (3ey - 4ez)
The Attempt at a Solution
(ex * ez) + (ex * (-4ez)) + (ez * 3ey) + ( ez * (-4ez)
now, these are all orthogonal to each other, so, for example, if I have ex * ey then I should end up with ez, shouldn't I?
So here is my solution.
= 3ez - 4ey + 3ex - 4ez
= 3ex - 4 ey + ez
The solution shown to be correct is -3ex + 4ey + 3ez
so what have I done wrong, please?