Prove that `4costhetacos(pi/3+theta)cos(pi/3-theta)=cos3theta`

Prove that: 4\ costhetacos\ (pi/3+theta)cos(pi/3-theta)=cos3theta

Prove that: 2cos theta cos((pi)/(3)+theta)cos((pi)/(3)-theta)=cos3 theta

The sum of all the solution of the equation costhetacos(pi/3+theta)cos(pi/3-theta)=1/4theta in [0,6pi]

Prove that cos theta +cos ((2pi)/(3)-theta)+cos ((2pi)/(3)+theta)=0

The sum of all the solution is of the equation cos theta cos ((pi)/3+theta)cos ((pi)/3-theta)=1/4, theta in [0,6pi ]

Prove that costhetacos""(theta)/(2)-cos3 thetacos""(9theta)/(2)=sin7thetasin8theta .

Prove that costhetacos""(theta)/(2)-cos3 thetacos""(9theta)/(2)=sin7thetasin8theta .

Prove that, costhetacos((theta)/(2))-cos3thetacos((9theta)/(2))=sin7thetasin8theta .

Prove that costhetacos((theta)/(2))-cos3thetacos((9theta)/(2))="sin"((7theta)/2)"sin"4theta