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

Prove that cos20^(@) cos40^(@) cos80^(@) = 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 : cos20^(@)cos40^(@)cos80^(@)=1/8

cos 40^(@) + cos 80^(@) + cos 160^(@) =

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

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

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

Prove that: cos20^(@)cos40^(@)cos80^(@)=1/8

Prove that: cos20^(@)cos40^(@)cos80^(@)=1/8

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