[" 2.Prove that: "cos A cos(60-A)cos(60+A)=(cos3A)/(4)],[" Prove that "]

Prove that : cos Acos(60-A)cos(60+A)=1/4cos3A

Prove that :cos A cos(60-A)cos(60+A)=(1)/(4)cos3A

Prove that: cos Acos(60^0-A)cos(60^0+A)=1/4cos3A

Prove that: cos A cos(60^(@)-A)cos(60^(@)+A)=(1)/(4)cos3A

Prove that cos3A=4cos^3 A-3cosA

Prove that: cosA. Cos(60^(@)+A)cos(60^(2)-A)=1/4 cos3A

(ii) Prove cos x cos(60-x)cos(60+x)=(1)/(4)cos3x

Prove that cos(60^(@)+A) + cos(60^(@)-A)-cosA=0

Prove that: (i) cos A cos(60^(@)-A)cos (60^(@)+A)=(1)/(4)cos 3A (ii) "tan" A+"tan"(60^(@)+A)-"tan"(60^(@)-A)=3 tan 3A .

Prove that 4cos12^(@)cos48^(@)cos72^(@)=cos36^(@)