2 A ^3 A - 2 ^3 A A = - Vidyadip

MCQ

$2\sin A{\cos ^3}A - 2{\sin ^3}A\cos A = $

A
$\sin 4A$
✓
$\frac{1}{2}\sin 4A$
C
$\frac{1}{4}\sin 4A$
D
None of these

✓

Answer

Correct option: B.

$\frac{1}{2}\sin 4A$

b
(b) $2\sin A{\cos ^3}A - 2{\sin ^3}A\cos A$

$ = 2\sin A\cos A({\cos ^2}A - {\sin ^2}A)$

$ = 2\sin A\cos A\cos 2A $

$= \sin 2A\cos 2A $

$= \frac{1}{2}\sin 4A$.

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