Question

16. Solve for the angle x. cos(¹/2x) = ¹/2

Answer 1

Answer:

We know that ,

$\rightarrow \tt \cos( \frac{\pi}{3} ) = \frac{1}{2}$

So ,

$\: \rightarrow \tt \cos( \frac{1}{2}x ) = \cos( \frac{\pi}{3} ) \\ \\ \rightarrow \tt \frac{1}{2}.x = \frac{\pi}{3} \\ \\ \rightarrow \tt x = \frac{2\pi}{3}$

we can add 2 pi to it since there will be no change in the value

Also,

$\: \rightarrow \tt \cos( \frac{14\pi}{6} ) = \frac{1}{2} \\ \\ \\ \rightarrow \tt \frac{1}{2} x = \frac{14\pi}{6} \\ \\ \rightarrow \tt x = \frac{7\pi}{3}$

Answer : Option B