Prove that `tan70^0=2tan50^0+tan20^0`

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

Prove that tan70^(@)-tan20^(@)-2tan40^(@)=4tan10^(@) . (b) In a DeltaABC , if a=2sqrt3,b=2sqrt2andC=75^(@) find the other side and the angles.

Prove that tan 70^(@)-tan 20^(@)-2 tan 40^(@)=4 tan 10^(@)

Show that tan1^0tan2^0.....tan89^0=1

Prove that tan2A =(2tanA)/(1-tan^2 A)

In acute angled triangle ABC prove that tan ^(2)A+tan^(2)B+tan^(2)Cge9 .

Prove that: sin10^0sin30^0sin50^0sin70^0=1/(16)dot

Prove that (1+tan1^0)(1+tan2^0)......(1+tan45^0)=2^(23)dot

Prove that (tan^(2)2theta-tan^(2)theta)/(1-tan^(2)2thetatan^(2)theta)=tan 3 theta tan theta .

Prove that (cos10^0+sin10^0)/(cos10^0-sin 10^0)=tan55^0