cos42^(@)+cos78^(@)+cos162^(@)

cos6^(@) cos42^(@) cos66^(@) cos78^(@) =

A.78^(@)-sin18^(@)+cos132^(@),B=cos12^(@)+cos84^(@)+cos132^(@)+cos156^(@) and C=(sin75^(@)+sin15^(@))/(cos75^(@)+cos15^(@)) then arrang in the ascending order

A=sin78^(@)-sin18^(@)+cos132^(@) B=cos12^(@)+cos84^(@)+cos132^(@)+cos156^(@) and C=(sin 75^(@)+sin 15^(@))/(cos 75^(@)+cos 15^(@)) then arrange in the ascending order

Show that cos 42^(@) + cos 78^(@) + cos 162^(@) = 0

4cos6^(@)cos42^(@)cos60^(@)cos78^(@)=

Prove that cos6^(@)*cos42^(@)*cos66^(@)cos78^(@)=(1)/(16)

Prove that cos 6^(@) cos 42^(@) cos 66^(@) cos 78^(@) =(1)/(16)

A=cos 20^(@)cos 40^(@) cos60^(@)cos 80^(@) , B=cos6^(@)cos42^(@)cos66^(@)cos78^(@) and C=cos 36^(@)cos72^(@)cos 108^(@)cos 144^(@) then