cos theta cos(60^(@)-theta)cos(60^(@)+theta)=(1)/(4)cos3 theta

Statement-1: The vlaue of cos20^(@)cos40^(@)cos60^(@)cos80^(@)is1/16. Statement-2: for any theta, cos thetacos(60^(@)-theta)cos(60^(@)+theta)=1/4cos3theta

Statement-1: The vlaue of cos20^(@)cos40^(@)cos60^(@)cos80^(@)is1/16. Statement-2: for any theta, cos thetacos(60^(@)-theta)cos(60^(@)+theta)=1/4cos3theta

Prove that cos thetacos(60^(@)- theta)cos(60^(@)+theta) = 1/4 cos 3 theta

cos(60^(@)-theta)cos(60^(@)+theta)=(1)/(4)(4cos^(2)theta-3)

Prove that: |cos theta cos(60^(@)-theta)cos(60^(@)+theta)<=(1)/(4) for all values of theta

The smallest positive angle theta (in degrees)satisfying the equation cos theta*cos(60^(@)-theta)*cos(60^(@)+theta)=(1)/(8) is equal to

Prove that 4 cos theta cos (60^(@) + theta) cos (60^(@) - theta) = cos 3theta .

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 sin (30^(@) + theta) + cos (60^(@) + theta) = cos theta