Prove that:`tan6^0tan42^0tan66^0tan78^0=1.`

Prove that tan6^@tan42^@tan66^@tan78^@=1

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

Prove that tan20^0tan40^0tan60^0tan80^0 =3

Show that tan6^@tan42^@tan66^@tan78^@=1

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

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

Prove that: t a n 20^0tan40^0tan60^0tan80^0=3

Prove that tan20^0tan40^0tan80^0=tan60^0

Prove that: tan20^0tan40^0tan80^0=tan60^0

Prove that tan20^0tan40^0tan80^0=tan60^0