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

Prove that cos^(3)A+cos^(3)(120^(@)+A)+cos^(3)(240^(0)+A)=(3)/(4)cos3A

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

Prove that cos^3A+cos^3(120^0+A)+cos^3(240^0+A)=3/4cos3A

The minimum value of cos^(3) x+ cos^(3) (120^(@) + x) + cos^(3) (120^(@) -x) is

4(cos^3 20^(@) + cos^(3) 40^(@))=

cos^(3)110^(@)+cos^(3)10^(@)+cos^(3)130^(@)=

cos^(3) 20^(@) + cos^(3) 100^(@) + cos^(3) 140^(@) =

Statement - I : Period of cos^(3) x + cos^(3) (120^(0) - x) + cos^(3) (120^(0) + x ) is (pi)/(3) Statement -II : Period of cos((2pi x)/ 3 ) + sin((pix)/2) - tan ((pi x )/ 4) is 12 Which of the above statement is correct.