40.4cos theta cos2 theta cos3 theta-2cos4 theta=1

4costheta cos 2theta cos3theta - 2cos 4theta=1

4cos6 theta cos4 theta cos2 theta=

If theta=(pi)/(9), prove that cos theta cos2 theta cos3 theta cos4 theta=(1)/(16)

1+cos2 theta+cos4 theta+cos6 theta=

cos theta cos2 theta cos3 theta=(1)/(4)

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

Prove that, If " "15 theta = pi, "show that," cos theta cos2 theta cos3theta cos 4theta cos5 theta cos6theta cos7theta =1/2^(7)

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 4theta = cos 3theta - cos2theta

If 13 theta =pi , " prove that " cos theta cos 2theta cos3 theta cos4theta cos5 theta cos6 theta =1/2^(6)