`cos 4theta = cos 3theta - cos2theta`

Prove that : (cos 4theta + cos 3theta + cos 2theta)/(sin 4theta + sin 3theta + sin 2theta) = cot 3theta

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 .

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

4cos6 theta cos4 theta cos2 theta=

Solve the following trigonometric equation : cos theta+ cos 3theta= cos 2 theta+ cos 4 theta .

cos 3theta+cos 5theta+cos 7theta+cos 9theta=4 cos theta cos 2theta cos 6theta .

If cos theta + cos 2theta + cos 3theta = 0 then theta =

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 .

What is the value of [(cos 3 theta + 2cos 5 theta+ cos 7 theta)/(cos theta + 2cos 3 theta + cos 5 theta)] + sin 2 theta tan 3 theta ? [(cos 3 theta + 2cos 5 theta+ cos 7 theta)/(cos theta + 2cos 3 theta + cos 5 theta)] + sin 2 theta tan 3 theta का मान क्या है?