" Q9.Prove that "cos^(2)x+cos^(2)(x+(pi)/(3))+cos^(2)(x-(pi)/(3))=(3)/(2)

Show that cos ^(2) x+cos ^(2)(x+(pi)/(3))+cos ^(2) (x-(pi)/(3))=(3)/(2)

Prove that: cos^(2)A+cos^(2)(A+(2 pi)/(3))+cos^(2)(A-(2 pi)/(3))=(3)/(2)

Find the value of cos^(2)x+cos^(2)(x+(pi)/(3))+cos^(2)(x-(pi)/(3))

Prove that cos^2x+cos^2(x+pi/3)+cos^2(x-pi/3)=3/2 .

Prove that: cos^2A+cos^2(A+(2pi)/3)+cos^2(A-(2pi)/3)=3/2

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

Prove that cos^(3)x+cos^(3)((2pi)/3+x)+cos^(3)((2pi)/3-x)=3/4 cos 3x

Prove that cos^(2)+x+cos^(2) (x+pi/3)+cos^(2)(x-pi/3)=3/2 and hence find the values of sin^(2)x +sin^(2) (x+pi/3)+sin^(2) (x-pi/3)

The range of cos^(2)(2(pi)/(3)-x)+cos^(2)(2(pi)/(3)+x) is

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