Tangent

In trigonometry, the tangent of an angle in a right triangle is defined as the ratio of the opposite and adjacent sides.

We can also see a relationship between the sine and cosine functions:

<math>\tan \theta = \frac{\sin \theta}{\cos \theta} = \cot \left(\frac{\pi}{2} - \theta \right) = \frac{1}{\cot \theta} \,</math>

In analytic geometry, a line which intersect a circle or curve at only one, unique point is said to be tangent to that circle or curve. At their point of intersection, the curve and the line have exactly the same slope.

Compare: Asymptote