Answer:
We know that ,
[tex] \rightarrow \tt \cos( \frac{\pi}{3} ) = \frac{1}{2} [/tex]
So ,
[tex] \: \rightarrow \tt \cos( \frac{1}{2}x ) = \cos( \frac{\pi}{3} ) \\ \\ \rightarrow \tt \frac{1}{2}.x = \frac{\pi}{3} \\ \\ \rightarrow \tt x = \frac{2\pi}{3} [/tex]
we can add 2 pi to it since there will be no change in the value
Also,
[tex] \: \rightarrow \tt \cos( \frac{14\pi}{6} ) = \frac{1}{2} \\ \\ \\ \rightarrow \tt \frac{1}{2} x = \frac{14\pi}{6} \\ \\ \rightarrow \tt x = \frac{7\pi}{3} [/tex]
Answer : Option B
