Question

Evaluate the expression.

r = <9, -7, -1>, v = <2, 2, -2>, w = <-5, -2, 6>

v ⋅ w

I keep doing it and I end up with (7,4,-8), which isn't one of my answer choices, what am I doing wrong?

Answer 1

dot product should be number, not vector.

Answer 2

Saying we have \(\large a = \langle a_x,a_y,a_z\rangle\) and \(\large b = \langle b_x, b_y, b_z \rangle\)

Then we have \(\large a\cdot b = a_xb_x+a_yb_y+a_zb_z\)

Answer 3

Oh okay so I'm doing v x w?

Answer 4

I just did it and ended up with -26

Answer 5

\(v\cdot w = -10+-4+-12 = \boxed{-26}\)

So yeah.