`4 cos 6 theta cos 4 theta cos 2 theta = `

4cos6 theta cos4 theta cos2 theta=

1+ cos 2 theta + cos 4 theta + cos 6 theta =

cos 4theta = cos 3theta - cos2theta

IF 11 theta = pi then cos theta . cos 2 theta . cos 3 theta cos 4 theta . Cos 5 theta is

Prove the following : cos 3 theta+ cos 5 theta+ cos 7 theta+ cos 9 theta= 4 cos theta cos 2 theta cos 6 theta .

Prove the following : cos 7 theta + cos 5 theta + cos 3 theta +cos theta =4 cos theta cos2 theta cos4 theta for all value of theta .

( cos 6 theta +6 cos 4 theta + 15 cos 2 theta + 10)/( cos 5 theta + 5 cos 3 theta + 10 cos theta)=

Show that, 32 sin^(6) theta = 10 - 15 cos 2 theta + 6 cos 4 theta - cos 6 theta

1+cos2 theta+cos4 theta+cos6 theta=

1 + (cos 2 theta + cos 6 theta)/(cos 4 theta) = (sin 3 theta)/(sin theta).