Given the vectors:
a=i+2y-k
b=2i-y+k
c=i+2k
Find vectors:
a+2b-c
---------------
Is it i, y & k?
---
2b = 4i - 2y + 2k
a = i + 2y - k
-c = -i - 2k
----------------------------- Add
4i - k
==================
a*c
If you mean the cross-product:
i y k
1 2 -1
-1 0 -2
----
= i*(-4) - y*(-2-1) + k*(2)
= -4i + 3y + 2k
======================
c·a
a=i+2y-k
c=i+0y+2k
--> 1*1 -1*2 = -1
=====================
(a*b)·c
----
Do like the ones above.