Prove that : `cos 36^@ cos 72^@ cos 108^@ cos 144^@ = 1/16`

Prove that (1)cos36^(@)cos72^(@)cos108^(@)cos144^(@)=(1)/(16)(2) Show that 4sin27^(@)=sqrt(5+sqrt(5))-sqrt(3-sqrt(5))

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

Prove that cos36^(@)cos72^(0)cos108^(0)cos144^(0)=(1)/(16)

Prove that cos 20^@ cos 40^@ cos60^@ cos80^@=1/16

cos36^(@)-cos72^(@)=

Prove that : cos36^@gttan36^@

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

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