`cos theta - cos (60^(@) + theta ) - cos(60^(@) - theta )= `

I : cos^2 theta + cos^(2) (60^@ + theta ) + cos^(2) (60^@ - theta ) = 3//2 II : sin^(2) theta + sin^(2)(60^(@) + theta ) + sin^(2)(60^(@) - theta ) =3//2

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

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

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

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

Evaluate sin(30^(@)+theta)-cos(60^(@)-theta) .

Evaluate sin(30^(@)+theta)-cos(60^(@)-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

Assertion (A):cos^(2)theta+cos^(2)(60^(@)-theta)+cos^(2)(60^(@)+theta)=(3)/(2)sin alpha-sin(120^(@)-alpha)+sin(120^(@)+alpha)=0