Q. 34.0( 6 Votes )
Prove that:
Answer :
We know that,
cos 3θ =4cos3θ–3cosθ
⇒4 cos3θ=cos3θ+3cosθ
And similarly
sin 3θ=3sin θ–4sin3 θ
⇒4 sin3θ=3sinθ–sin 3θ
Now,
Substituting the values from equation (i) and (ii), we get
(as sin(x+y) = sin x cos y+cos x sin y)
RHS
Hence Proved
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