`cos^2(theta+phi)-sin^2(theta-phi)=cos2thetacos2phi` U Juli 2UT 4CUL48 = Cote- cos2(0+0) - sin(-) = cos 20 cos 20

cos2thetacos2phi+sin^2(theta-phi)-sin^2(theta+phi)=

cos2thetacos2phi+sin^(2)(theta-phi)-sin^(2)(theta+phi) is equal to

Prove that, cos^(2) (theta + phi) - sin^(2) (theta - phi) = cos 2 theta cos 2 phi

cos2 theta cos2 phi+sin^(2)(theta-phi)-sin^(2)(theta+phi)=cos(2 theta+2 phi)

cos 2 (theta+ phi) +4 cos (theta + phi ) sin theta sin phi + 2 sin ^(2) phi=

cos 2 (theta+ phi) +4 cos (theta + phi ) sin theta sin phi + 2 sin ^(2) phi=

cos 2theta cos 2phi + sin^(2) (theta - phi ) - sin^(2) ( theta + phi) is equal to

Prove that sin^2(theta-phi)-sin^2(theta+phi)= -sin2theta sin2phi hence prove that cos2thetacos2phi-sin^2(theta+phi)+sin^2(theta-phi)=cos(2theta+2phi)