cos4 theta=cos2 theta

Solve the following equation: cos4theta=cos2theta

sin^2theta+cos^4theta=cos^2theta+sin^4theta

Find the general solution of the following equation: cos4theta = cos2theta

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 .

Prove that cos theta cos 2 theta cos 4 theta…. Cos 2 ^(n-1) theta = ( sin ( 2 ^(n) theta))/( 2 ^(n) (sin theta)) .

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

(cos4 theta+cos3 theta+cos2 theta)/(sin4 theta+sin3 theta+sin2 theta)=cot3 theta

Prove that : (cos4 theta+cos3 theta+cos2 theta)/(sin4 theta+sin3 theta+sin2 theta)=cot3 theta

Prove that: (cos6 theta+6cos4 theta+15cos2 theta+10)/(cos5 theta+5cos3 theta+10cos theta)=2cos theta

Express the following as a sum or difference of two trignometric functions, 2cos4theta cos2theta