Mark the Correct alternative in the following:
2(1 – 2 sin2 7x) sin 3x is equal to
Given expression is 2(1 – 2 sin2 7x) sin 3x
2(1 – 2 sin2 7x) sin 3x = 2 cos 2(7x) sin 3x
[ using cos 2A = 1 – 2sin2A ]
= 2 cos 14x sin 3x
[using the sum of angles formula 
]
= sin (17x) – sin (11x)
Therefore 2(1 – 2 sin2 7x) sin 3x = sin (17x) – sin (11x)
The answer is option A.
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