Tangent of Angle minus Three Right Angles

Theorem

 * $\map \tan {x - \dfrac {3 \pi} 2} = \cot x$

Also see

 * Sine of Angle plus Three Right Angles
 * Cosine of Angle plus Three Right Angles
 * Cotangent of Angle plus Three Right Angles
 * Secant of Angle plus Three Right Angles
 * Cosecant of Angle plus Three Right Angles