Question

How do I find the angle between two vectors using the law of cosines?

Answer 1

Law of Cosines for Vectors

`vec{v} cdot vec{w}=|vec{v}||vec{w}|cos theta`

By solving for `theta`,

`Rightarrow cos theta={vec{v}cdot vec{w}}/{|vec{v}||vec{w}|} Rightarrow theta=cos^{-1}({vec{v}cdot vec{w}}/{|vec{v}||vec{w}|})`

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I hope that this was helpful.