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

Question

solomonzelman · Answer

$\LARGE\color{blue}{ \bf     cos~\frac{-5π}{3}	 }$

$\LARGE\color{blue}{ \bf     cos~\frac{-5(180)}{3}	 }$

$\LARGE\color{blue}{ \bf     cos~(-300)	 }$

$\LARGE\color{blue}{ \bf     cos~(300)	 }$

$\LARGE\color{blue}{ \bf     cos~(360-60)	 }$

can you go on from here, or still need help ?

solomonzelman · Answer

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

anonymous · Answer

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