Question

Question ? 3 3. State Pas CT, 4 cos? x sin 3x + 4 sin? x cos 3x = 3 sin 4x.
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Answer 1

Answer:

Let us consider the LHS sin 4x As we know, sin 2x = 2 sin x cos x cos 2x = cos2 x – sin2 x Therefore, sin 4x = 2 sin 2x cos 2x = 2(2 sin x cos x) (cos2 x – sin2 x) = 4 sin x cos x (cos2 x – sin2 x) = 4 sin x cos3 x – 4 sin3 x cos x = RHS Thus proved.Read more on Sarthaks.com - https://www.sarthaks.com/658583/prove-the-identity-sin-4x-4-sin-x-cos-3-x-4-cos-x-sin-3-x?show=658590#a658590