`costheta-cos3theta+cos5theta-cos7theta=4sinthetasin4thetacos2theta`

cos theta-cos3 theta+cos5 theta-cos7 theta=4sin theta sin4 theta cos2 theta

cos3thetacos5theta-cos7thetacos9theta=0

costheta.cos2theta.cos3theta=1/4

Solve: costheta+cos3theta+cos5theta+cos7theta=0

Solve: costheta+cos3theta+cos5theta+cos7theta=0

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

Prove that: a) cotthetacot(60^(@)-theta)cot(60^(@)+theta)=cot3theta b) cos5theta=16cos^(5)theta-2thetacos^(3)theta+5costheta c) sin4theta=4sinthetacos^(3)theta-4costhetasin^(3)theta

Prove that: a) cotthetacot(60^(@)-theta)cot(60^(@)+theta)=cot3theta b) cos5theta=16cos^(5)theta-2thetacos^(3)theta+5costheta c) sin4theta=4sinthetacos^(3)theta-4costhetasin^(3)theta

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

Prove that, 1/(costheta-cos3theta)+1/(costheta-cos5theta)+1/(costheta-cos7theta)+…+to n terms = 1/(2sintheta) [cottheta-cot(n+1)theta]