Question

Math: https://snipboard.io/5Zk027.jpg
Options: https://snipboard.io/DHMBZq.jpg

Answer 1

\[\cos 2\theta=1-2 \sin ^2\]
\[\cos 2\theta=\frac{ \sqrt{3} }{ 2}=\cos \frac{ \pi }{ 6 },\cos (2\pi-\frac{ \pi }{ 6})\]
\[\cos 2\theta=\cos (2n \pi+\frac{ \pi }{ 6}),\cos (2n \pi+\frac{ 11\pi }{ 6})\]
\[2\theta=2n \pi+\frac{ \pi }{ 6 },2n \pi+\frac{ 11\pi }{ 6}\]
\[\theta=n \pi+\frac{ \pi }{ 12 },n \pi+\frac{ 11\pi }{ 12 },n \in ~R\]

Answer 2

THANKS!

Answer 3

so it would be option D.) ?