Use the given vectors to find the indicated quantities. u = 〈2, −5〉, v = 〈−3, −4〉, w = 〈2, −1〉

Question

-4u ∙ v = ___

Answer 1

Does Scalar Multiplication take priority over dot product?

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k (u1, u2) dot (v1, v2) =

(k*u1, k*u2) dot (v1,v2) =

k*u1*v1 + k*u2*v2

versus

k [ (u1,u2) dot (v1,v2)] =

k ( u1 v1 + u2 v2) ]=

k u1 v1 + k u2 v2

same result....

see, watch................

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4U = <8, -20) and then 4U dot V = <8, -20> dot <-3,-4>

-24 + 80

= 56

otherwise....

U . V = 2 * -3 + -5 * -4

= -6 + 20

= 14

and 14*4 = 56