Question

Determine (6i+2j)· (i-4j+k)

This is a dot product question and each letter has the vector symbol

Answer 1

in the x direction 6 * 1 = 6
int the y direction 2 * -4 = -8
in the z direction 0 * 1 = 0
6 + -8 = -2
see:
http://www.mathsisfun.com/algebra/vectors-dot-product.html
to see how to do it with
|A| * |B| * cos theta