asech.c File Reference

Inverse hyperbolic secant function. More...

#include "prim.h"

Include dependency graph for asech.c:

Go to the source code of this file.

Functions
double	asech (double x)
	Inverse hyperbolic secant function. More...

Detailed Description

Inverse hyperbolic secant function.

Definition in file asech.c.

Function Documentation

asech()

double asech

(

double

x

)

Inverse hyperbolic secant function.

Method
                    1+sqrt(1-x*x)
    asech(x) = ln( ------------— )
                          x
    when x <= 0
    asech(x) = NaN

    when x > 1
    asech(x) = NaN

Definition at line 52 of file asech.c.

References log(), and sqrt().

Referenced by RealNumber::HypArcSecant().

{
    double a, b, c, d, e, f;

    if (TRIG_INEXACT(x) || x < 0.0 || x > 1.0)
    {
        return NAN;
    }

    a = x * x;
    b = 1.0 - a;
    c = sqrt(b);
    d = 1.0 + c;
    e = d / x;
    f = log(e);
    return f;
}

Here is the call graph for this function:

Here is the caller graph for this function: