Computes the hyperbolic cotangent of a number.
input value
hyperbolic cotangent
var v = coth( 0.0 ); // returns Infinity
var v = coth( 2.0 ); // returns ~1.0373
var v = coth( -2.0 ); // returns ~-1.0373
var v = coth( NaN ); // returns NaN
Computes the hyperbolic cotangent of a number.