The two-dimensional vectors
A
and
B
both have magnitudes of 5.25 m. If
A + B = (3i) m,
what is the angle between
A
and
B?
(Enter the magnitude.)
if you draw a diagram, you can see that the law of cosines gives you
5.25^2 + 5.25^2 + 2*5.25^2 cosθ = 9
cosθ = -0.836
now finish it off