Question

If |u| = 12, |v| = 8, and u · v = 48, then the angle between |u| and |v| is _____.



0°

30°

60°

90°

Answer 1

Well considering

\[\large \vec{a} \cdot \vec{b} = |a||b|cos\theta \]

we know that

\[\large cos\theta = \frac{\vec{a} \cdot \vec{b}}{|a||b|}\]

Answer 2

90??

Answer 3

Not quite what I get

so \[\large \theta = cos^{-1}\frac{48}{96}\]
\[\large \theta = ?\]

Answer 4

OMG ITS 60!

Answer 5

There we go :)