Question

what is the exact value of cos(-5*pi over3)

Answer 1

\(\LARGE\color{blue}{ \bf cos~\frac{-5π}{3} }\)

\(\LARGE\color{blue}{ \bf cos~\frac{-5(180)}{3} }\)

\(\LARGE\color{blue}{ \bf cos~(-300) }\)

\(\LARGE\color{blue}{ \bf cos~(300) }\)

\(\LARGE\color{blue}{ \bf cos~(360-60) }\)

can you go on from here, or still need help ?

Answer 2

\(\LARGE\color{blue}{ \bf cos~(A-B)=cosAcosB+sinAsinB }\)

Answer 3

\[\cos \left( -\theta \right) =\cos \theta \]
\[\cos \left( \frac{ 5 \pi }{ 3} \right)=\cos \left( 2 \pi-\frac{ \pi }{ 3 } \right)=\cos \frac{ \pi }{ 3 }=?\]