`CosA+cos(120+A)+cos(120-A)`

cosA + cos (A + 120) + cos (120 - A) = 0

cos120^(@)=

Prove the following: (i) "sin" alpha+"sin"(alpha+(2pi)/(3))+"sin"(alpha+(4pi)/(3))=0 (ii) cos A+cos(120^(@)-A)+cos(120^(@)+A)=0 .

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

Prove that cos(120^@-A)+cosA+cos(120^@+A)=0 .

cosA+cos(240^(@)+A)+cos(240^(@)-A)=?

cos (120^(@)) is -

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

For any angle theta , costheta+cos(120^@+theta)+cos(120^@-theta)=........

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