Mathematics

Problem

Let

\vec{a}=(\cos30^{\circ},\sin30^{\circ})

and

\vec{b}=(\cos75^{\circ},\sin75^{\circ})

. Find

\vec{a}\,\cdot\,\vec{b}

. a)

\cos60^{\circ}

\cos105^{\circ}

\cos45^{\circ}

\cos15^{\circ}