" N) Prove that,"cos20^(@)*cos40^(@)cos80^(@)=(1)/(8)

Prove that cos 20^(@) cos 40^(@) cos 80^(@)=1/8

Prove that cos 20^(@) cos 40^(@) cos 80^(@)=1/8

Prove that: cos40^(@)cos80^(@)cos160^(@)=-(1)/(8)

(a) If f(x)=(x-1)/(x+1) then show that. (i) f((1)/(x))=-f(x) (ii) f(-(1)/(x))=-(1)/(f(x)) . (b) Prove that cos20^(@)cos40^(@)cos80^(@)=1//8

Prove that, cos80^(@)+cos40^(@)-cos20^(@)=0

Prove that cos 20^(@) cos 40^(@) cos 80^(@) = (1)/(8).

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

Prove that: cos80^(@)+cos40^(@)-cos20^(@)=0

Prove that cos80^(@)+cos40^(@)-cos20^(@)=0 .

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