Evaluate the expression: v ⋅ w Given the vectors: r = <5, -5, -2>; v = <2, -8, -8>; w = <-2, 6, -5>

Question

Precalculus

Answer 1

Hi Rosanne,

 

If you have a vector a = [ax ay az] and b = [bx by bz], both in x-y-z Cartesian space, the dot product a•b is given by:

 

a•b = axbx + ayby + azbz

 

So, you have v = [2 -8 -8] and w = [-2 6 -5].

 

So, v•w = (2)(-2) + (-8)(6) + (-8)(-5) = -4 - 48 + 40 = -12