Question

Find the angle between the vectors u and v if u = (1, 2) and v = (- 4, - 2). Round answer to two decimal places.
A.141.20o
B.141.89o
C. 143.13o
D. 144.09o
E. 144.54o

Answer 1

use scalarproduct and acos

Answer 2

ok well I don't know what scalarproduct is but I have
cosθ=u.v/IIuII IIvII

Answer 3

yes, that u.v is the scalarproduct.

Answer 4

the angle between vector is cool....

Answer 5

u.v
----
|u||v|

Answer 6

<1,2> . <-4,-2> = -4 + -4 = -8
------------------------- ---
sqrt(5) sqrt(20) = sqrt(100) = 10

cos(t) = -4/5

Answer 7

t = cos^-1(-4/5)

Answer 8

t = 143.13

Answer 9

ive been reading about vectors allll week ;)

Answer 10

and that is the extent of my knowledge so far lol

Answer 11

Thank you this actually make's sense too... I was missing the t=cos^-1(-4/5)

Answer 12

your welcome ;)