Prove that : `tan 20^0 tan 40^0 tan 60^0 tan 80^0 =3`

Prove that: tan20^(@)tan40^(@)tan60^(@)tan80^(@)=3

Prove that tan20^(@)tan40^(@)tan80^(@)=tan60^(@)

Prove that: tan20^(@)tan40^(@)tan80^(@)=tan60^(@)

Prove that: tan10^(@) tan20^(@)tan70^(@)tan80^(@)=1

Prove that: tan10^0tan15^0tan75^0tan80^0=1 tan1^0tan2^0tan3^0tan89^0=1 cos1^0cos2^0cos3^0cos180^0=0

Prove that: tan20^(@)tan30^(@)tan40^(@)tan80^(@)=1

tan20^(@)tan40^(@)tan60^(@)tan80^(@)

Prove that: tan6^(0)tan42^(0)tan66^(@)tan78^(@)=1

Prove the following: (i) "tan" 20^(@) tan 40^(@) tan 60^(@) tan 80^(@)=3 (ii) "tan" 20^(@) tan 40^(@) tan 80^(@)="tan" 60^(@) .

tan20^(@)tan40^(@)tan60^(@)tan80^(@)=?