Question

if 2cos teta =√3 prove that 3 sin teta - 4sin^3 teta= 1​

Answer 1

2 cos theta = √3

or cos theta = √3/2

or cos theta = cos 30° [cos 30° = √3/2]

LHS

= 3 sin theta - 4sin³ theta

= 3 sin 30° - 4 sin³ 30°

= 3*1/2 - 4*(1/2)³

= 3/2 - 4/8

= 3/2 - 1/2

= 2/2

= 1

= RHS