Required Answer -:
16cos³ x sin² x
2cos x - ( cos 3x + cos 5x )
= 2cos x - 2 cos 4x cos x
= 2cos x 2sin² 2x
= 4 cos x ( 2sin x cos x)²
= 16cos³ x sin² x
Thus,, the value of 2 cos x - cos 3x - cos 5x is = 16cos³ x sin² x
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