Q. If $\tan \, \theta + \tan (\theta + \frac{\pi}{3}) + \tan (\theta + = 3,$ then which of the following is equal to $1$ ?

Solution:

Given,
$\tan \theta+\tan \theta+\frac{\pi}{3}+\tan \theta+\frac{2 \pi}{3}=3$
$\Rightarrow \tan \theta+\frac{\tan \theta+\overline{3}}{1-\overline{3} \tan $\theta}+\frac{\tan \theta-\overline{3}}{1+\overline{3} \tan ^{2} \theta}=3$
$\Rightarrow \tan \theta+\frac{8 \tan \theta}{1-3 \tan ^{2} \theta}=3$
$\Rightarrow \frac{9 \tan \theta-3 \tan ^{2} \theta}{1-3 \tan ^{2} \theta}=3$
$\Rightarrow 3 \tan 3 \theta=3$
$\Rightarrow \tan 3 \theta=1$