Question

Find the angle between the vectors u and v if u = (- 1, 1) and v = (3, 1). Round answer to two decimal places.

A.



114.64o


B.



115.33o


C.



116.57o


D.



117.53o


E.



117.98o

Answer 1

cos(t) = v.u/|v||u|

t = cos^-1(v.u/|v||u|)

Answer 2

The angle between a horizontal line. ( say the x axis) and 1,1 is 45
The angle between the horizontal and 3,1 is 15.

Answer 3

So the angle should be 30

Answer 4

the angle is measured in counter clockwise rotation

Answer 5

ok so amistre.... I have that formula and plugged in my numbers

-2/llull llvll

Answer 6

-1,1
3,1
-----
-3+1 = -2 = v.u

Answer 7

right i got that

Answer 8

|v| = sqrt(2); |u| = sqrt(10) = sqrt(20) = 2sqrt(5)

Answer 9

-2
------- = -1/sqrt(5) right?
2 sqrt(5)

Answer 10

yes when simplified noew I take the arc cos of that

Answer 11

*now

Answer 12

so it's looking like c

Answer 13

cos^-1(-1/sqrt(5)) = ....

116.5650

Answer 14

C is it :)