Secant of Supplementary Angle

Theorem

 * $\sec \left({\pi - \theta}\right) = -\sec \theta$

where $\sec$ denotes secant.

That is, the secant of an angle is the negative of its supplement.

Also see

 * Sine of Supplementary Angle
 * Cosine of Supplementary Angle
 * Tangent of Supplementary Angle
 * Cotangent of Supplementary Angle
 * Cosecant of Supplementary Angle