$$\tan 3 \theta . \tan 2 \theta . \tan \theta = \tan 3 \theta + \tan 2 \theta + \tan \theta$$
$\frac{3}{\left(\cos(\theta )\left(3\left(\sin(\theta )\right)^{2}-\left(\cos(\theta )\right)^{2}\right)\right)^{2}}$
$\frac{\tan(\theta )\left(3\left(\cos(\theta )\right)^{2}-\left(\sin(\theta )\right)^{2}\right)}{\left(\cos(\theta )\right)^{2}-3\left(\sin(\theta )\right)^{2}}$
