Prove that `4cos12^@cos48^@cos72^@=cos36^@`

Prove that: 4"cos"12^0cos48^0cos72^0=cos36^0

Prove that: 4cos12^(0)cos48^(0)cos72^(0)=cos36^(@)

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

cos48^(@)*cos12^(@)=

cos48^(@)*cos12^(@)=

cos12^(@)cos24^(@)cos48^(@)cos84^(@)

Prove that (sin18^(@))/(cos72^(@))=1

Prove that cos36^(@)cos72^(@)cos108^(@)cos144^(@)=1//16 .