Computes the hyperbolic arccosecant of a number.
input value
hyperbolic arccosecant
var v = acsch( 0 ); // returns NaN
var v = acsch( -1.0 ); // returns ~-0.881
var v = acsch( 1.0 ); // returns ~0.881
Computes the hyperbolic arccosecant of a number.