cos20^(@)*cos40^(@)*cos60^(@)*cos80=?

Prove that cos 20^(@)cos40^(@)cos60^(@)cos80^(@)=(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

The value of cos 20^(@) cos 40^(@)cos 60^(@) cos 80^(@) is equal to

The value of cos 20^(@) cos 40^(@)cos 60^(@) cos 80^(@) is equal to .............. A) 1/16 B) 3/16 C) (sqrt3)/(16) D) (sqrt3)/(32)

cos 20^(@)* cos 40^(@) * cos 60^(@) * cos 80^(@) =

cos 20^(@) cos 40^(@) cos 80^(@)=

cos20^(0)cos40^(0)cos60^(0)cos80^(0) is equal to

Prove that cos 80^(@) cos40^(@)+cos40^(@) cos200^(@) +cos200^(@) cos 80^(@) = -3/4

if sin2A=2sin A cos A and sin20^(@)=K then the value of cos20^(@)cos40^(@)cos80^(@)cos160^(@)-