2 + 2 + 2 4 = - Vidyadip

MCQ

$\sqrt {2 + \sqrt {2 + 2\cos 4\theta } } = $

A
$\cos \theta $
B
$\sin \theta $
✓
$2\cos \theta $
D
$2\sin \theta $

✓

Answer

Correct option: C.

$2\cos \theta $

c
(c) $\sqrt {2 + \sqrt {2 + 2\cos 4\theta } } $

$=\sqrt {2 + \sqrt {2.2{{\cos }^2}2\theta } } $

$ = \sqrt {2 + 2\cos 2\theta }$

$= \sqrt {4{{\cos }^2}\theta } $

$= 2\cos \theta $.

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