x+f(05^(2)A+cos^(2)(120+A)+cos^(2)(120-A)=(3)/(2)

cos^(3)A+cos^(120+A)+cos^(240+A)=(3)/(4)cos3A

cos^(2) A + cos^(2) ( 120^(@) + A)+ cos^(2) (120^(@) - A )=

The minimum of cos^(2)(120^(@) + x)+ cos^(2) (120^(@) -x) is

Prove that cos ^(2) A + cos ^(2) (A + 120^(@)) + cos ^(2) (A -120^(@)) = (3)/(2)

Prove that : cos^2 A+cos^2 (A+120^@)+ cos^2 (A-120^@)=3/2 .

Find the maximum value of cos^(3)x+cos^(3)(120-x)+cos^(3)(120+x)

Prove the following: cos^2x+cos^2(x+120^@)+cos^2(x-120^@)=3/2

Prove that : cos^(2)A+cos^(2)(A+pi/3)+cos^(2)(A-pi/3) =1/2[2cos^(2)A+2cos^(2)(A+60^(@))+2cos^(2)(A-60^(@))] =1/2[1+cos2A+1+cos(2A+120^(@))+1+cos(2A-120^(@))] 1/2[3+cos2A+cos(2A+120^(@))+cos(2A-120^(@))] 1/2[3+cos2A+2cos(2A+120^(@)+2A-120^(@))/(2).cos(2A+120^(@)-2A+120^(@))/(2)] =1/2[3+cos2A+2cos2Acos120^(@)] =1/2[3cos2A+2cos2Acos(90^(@)+30^(@))] =1/2[3+cos2A-2.cos2A.(1/2)] =1/2(3+cos2A-cos2A) =3/2 = RHS Hence Proved.