" 68.Prove that: "cos10^(0)cos30^(@)cos50^(@)cos70^(@)=(3)/(16)

Prove that cos10^(@)cos30^(@)cos50^(@)cos70^(@)=(3)/(16)

Prove that cos10^(@)cos30^(@)cos50^(@)cos70^(@)=(3)/(16)

cos10^(0)cos30^(0)cos50^(@)cos70^(0)

cos 10^(@) cos 30^(@) cos 50^(@) cos 70^(@) =(3)/(16)

Prove that: i) cos10^(@)cos30^(@)cos50^(@)cos70^(@)=3/16 ii) cos20^(@)cos40^(@)cos60^(@)cos80^(@)=1/16 iii) 4cos12^(@)cos48^(@)cos72^(@)=cos36^(@) iv) cos40^(@) cos80^(@)cos160^(@)=-1/8

Prove that: i) cos10^(@)cos30^(@)cos50^(@)cos70^(@)=3/16 ii) cos20^(@)cos40^(@)cos60^(@)cos80^(@)=1/16 iii) 4cos12^(@)cos48^(@)cos72^(@)=cos36^(@) iv) cos40^(@) cos80^(@)cos160^(@)=-1/8

Prove that: s in80^(@)-cos70^(@)=cos50^(@)

Prove that cos 2 0^(@)cos4 0^(@)cos6 0^(@)cos8 0^(@)=1/16

cos 10^(@) cos 30^(@) cos 50^(@) cos 70^(@) =