If `theta=(pi)/(7), ` show that `cos theta cos 2theta cos 3 theta = (1)/(8)`.

Solve cos theta+cos 2theta+cos 3theta=0 .

Solve cos theta * cos 2 theta * cos 3 theta = (1)/( 4), 0 le theta le pi

If theta = (pi)/(2 ^(n) +1) prove that 2 ^(n) cos theta cos 2 theta cos 2 ^(2) theta…. Cos 2 ^(n -1) theta =1

Solve cos theta+cos 7 theta+cos 3theta+cos 5 theta=0 ,

Find all value of theta , between 0 & pi , which satisfy the equation; cos theta * cos 2 theta * cos 3theta = 1/4 .

If 5 tan theta = 4 , show that ( 5 sin theta - 3 cos theta)/(5 sin theta + 3 cos theta) = (1)/(7)

If theta=20^(@) , then 8cos^(3)theta-6 cos theta is

Find all the values of theta satisfying the equation cos 2 theta - cos 8 theta + cos 6 theta =1, such that 0 le theta le pi.

cos ^(2) 2 theta - sin ^(2) theta = cos theta . cos 3 theta.

If (2^n+1)theta=pi then 2^n costheta cos2theta cos2^2 theta .......cos 2^(n-1) theta=