ArcSec[z] gives the arc secant of the complex number z.
Mathematical function (see Section A.3.10).
All results are given in radians.
For real z outside the interval to , the results are always in the range to , excluding .
ArcSec[z] has a branch cut discontinuity in the complex z plane running from to .
See Section 3.2.6.
New in Version 1.