function asech( x ) {
	return acosh( 1.0 / x );
}
Computes the hyperbolic arcsecant of a number.

## Method

```tex
\operatorname{asech}(x) = \operatorname{acosh}(\frac{1}{x})
```

@param {number} x - input value
@returns {number} hyperbolic arcsecant

@example
var v = asech( 1.0 );
// returns 0.0

@example
var v = asech( 0.5 );
// returns ~1.317

@example
var v = asech( NaN );
// returns NaN