सिध्द कीजिए कि : `cos^(3) theta+ cos^(3) (120^(@)+ theta) + cos^(3) (240^(@) + theta ) = (3)/(4) cos 3 theta`

cos^(3) theta + cos^(3) ( 120^(@) +theta ) + cos^(3) (120^(@) - theta )=

Prove that cos theta + cos (120^(@) + theta) + cos ( 120^(@)-theta) =0. Hence deduce that cos ^(3) theta + cos ^(3) ( 120^(@) + theta ) + cos^3( 120^(@)-theta) = 3/4 cos 3 theta.

If cos^(3) theta + cos^(3)((2pi)/(3) + theta) + cos^(3)((4pi)/(3) + theta) = a cos 3 theta , then a =

The value of cos ^(3) theta + cos ^(3) (theta +120^(@)) + cos ^(3) (120- theta^(@)) is

The value of cos ^(3) theta + cos ^(3) (theta +120^(@)) + cos ^(3) (theta- 120^(@)) is

2 cos theta - cos 3 theta - cos 5 theta - 16 cos^(3) theta sin^(2) theta =