What is the Value of Tan 120 Degrees ?

Solution :

The value of tan 120 degrees is $-\sqrt{3}$.

Proof :

We Know that tan 60 = $\sqrt{3}$.

By using formula of tan 2A,

tan 120 = $2 tan 60\over 1 – tan^2 60$ = $2 \times \sqrt{3}\over 1 – 3$

$\implies$  tan 120 = $-\sqrt{3}$