Determine tan(θ) from the unit circle at point P(x,y)
To determine $ \tan(\theta) $ from the unit circle at point $ P(x,y) $, recall that
$$ \tan(\theta) = \frac{\sin(\theta)}{\cos(\theta)} $$
On the unit circle, you have $ P(x,y) = (\cos(\theta), \sin(\theta)) $, so
$$ \tan(\theta) = \frac{y}{x} $$
Ensure that $ x \neq 0 $ to avoid division by zero.