Question

Prove that sin 2x + 2 Sin 4x + 6 X equal to 4 cos square x sin 4x

Answer 1

Hiii

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L.H.S. = sin 2 x + 2 sin 4 x + sin 6 x

= [sin 2 x + sin 6 x ] + 2 sin 4x

= 2 sin 4 x cos 2 x + 2 sin 4x

= 2 sin 4 x cos 2 x + 2 sin 4x

= 2 sin 4 x (cos 2 x + 1)

= 2sin4x(2cos² x -1+1)......................(cos2x = 2cos²x-1)

= 2 sin 4 x (2 cos ²x )

= 4cos² x sin 4 x

= R.H.S.

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Hope it will help u................