How do you evaluate $cos (- 30)$ $cos (-30)$ ?

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Answer 1 · 2018-03-31T23:51:25

$cos (- 30) = \frac{1}{2} \sqrt{3}$ $cos(-30)=1/2sqrt3$

For any angle, $cos ϑ = cos (- ϑ)$ $cosvartheta=cos(-vartheta)$

So

$cos (- 30) = cos 30 = cos (\frac{1}{6} π) = \frac{\sqrt{3}}{2} = \frac{1}{2} \sqrt{3}$ $cos(-30)=cos30=cos(1/6pi)=sqrt3/2=1/2sqrt3$

How do you evaluate cos(−30)cos (-30)?