cos20^(@)*cos40^(@)*cos80^(@)

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

cos20^(@).cos40^(@).cos60^(@).cos80^(@) is :

cos20^(@).cos40^(@).cos60^(@).cos80^(@)=1/16

cos20^(@).cos40^(@).cos60^(@).cos80^(@)=1/16

Prove that :cos20^(@)cos40^(@)cos60^(@)cos80^(@)=(1)/(16)

Prove that cos20^(@)cos40^(@)cos60^(@)cos80^(@)=(1)/(16)

Prove that: cos20^(@)cos40^(@)cos60^(@)cos80^(@)=(1)/(16)

Prove that cos 20^(@)cos40^(@)cos60^(@)cos80^(@)=(1)/(16)

A=cos20^(@)cos40^(@)cos60^(@)cos80^(@),B=cos60cos42^(@)cos66^(@)cos78^(@) and C=cos36^(@)cos72^(@)cos108^(@)cos144^(@) then