Returns the inverse hyperbolic secant of the given angle.
HASEC(Angle)
Angle is the angle in radians for which you want the inverse hyperbolic secant.
Formula

Description 
=HASEC(1.047)  Inverse
hyperbolic secant of 1.047 radians 
=HASEC (60*PI()/180)  Inverse
hyperbolic secant of 60 degrees (0.5) 
=HASEC (RADIANS(60))  Inverse
hyperbolic secant of 60 degrees (0.5) 