Mathematics

Problem

Which one of the following correctly expresses the scalar (dot) product of two vectors

\vec{a}

and

\vec{b}

in terms of the angle

\theta

between them? a)

|\vec a|\,|\vec b|\sin\theta

|\vec a|\,|\vec b|\cos\theta

\dfrac{|\vec a|}{|\vec b|}\cos\theta

|\vec a|\,|\vec b|\cos^{2}\theta