# Math Help - find angle between vectors .. confusion.

1. ## find angle between vectors .. confusion.

u * v / |u| |v| = cos theta

how is -14/39 = cos theta = 1.94?

if -14/(13 * 3) = cos theta

2. Originally Posted by rcmango
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if -14/(13 * 3) = cos theta

...

Hello,

you have: cos(θ) = -14/39. Now use the arccos-function:

arccos(-14/39) = 1.9379651...

EB

3. Originally Posted by rcmango
-14/39 = cos theta = 1.94