Cotangent of Right Angle

Theorem

 * $\cot 90 \degrees = \cot \dfrac \pi 2 = 0$

where $\cot$ denotes cotangent.

Also see

 * Sine of Right Angle
 * Cosine of Right Angle
 * Tangent of Right Angle
 * Secant of Right Angle
 * Cosecant of Right Angle