Sum of Arcsecant and Arccosecant

Theorem
Let:
 * $\mathrm {arcsec} \ x$ be the arcsecant of $x$.
 * $\mathrm {arccsc} \ x$ be the arccosecant of $x$.

Then $\mathrm {arcsec}\ x + \mathrm {arccsc} \ x = \dfrac \pi 2$.