com.imsl.math

Class Hyperbolic

java.lang.Object

com.imsl.math.Hyperbolic

public class Hyperbolic
extends Object

Pure Java implementation of the hyperbolic functions and their inverses.

This Java code is based on C code in the package fdlibm, which can be obtained from www.netlib.org. The original fdlibm C code contains the following notice.

Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.

Developed at SunSoft, a Sun Microsystems, Inc. business. Permission to use, copy, modify, and distribute this software is freely granted, provided that this notice is preserved.

Author:

Sun Microsystems (original C code in fdlibm), John F. Brophy (translated from C to Java)

See Also:

Example

Method Summary

Modifier and Type	Method and Description
static double	acosh(double x) Returns the inverse hyperbolic cosine of its argument.
static double	asinh(double x) Returns the inverse hyperbolic sine of its argument.
static double	atanh(double x) Returns the inverse hyperbolic tangent of its argument.
static double	cosh(double x) Returns the hyperbolic cosine of its argument.
static double	expm1(double x) Returns exp(x)-1, the exponential of x minus 1.
static double	log1p(double x) Returns log(1+x), the logarithm of (x plus 1).
static double	sinh(double x) Returns the hyperbolic sine of its argument.
static double	tanh(double x) Returns the hyperbolic tangent of its argument.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

expm1

public static double expm1(double x)

Returns exp(x)-1, the exponential of x minus 1. Specifically,
\({\rm expm1}(\pm 0)\) returns \(\pm 0\)
\({\rm expm1}(+\infty)\) returns \(\pm \infty\)
\({\rm expm1}(-\infty)\) returns -1.

Parameters:

x - a double specifying the argument.

Returns:

a double value representing exp(x)-1.

log1p

public static double log1p(double x)

Returns log(1+x), the logarithm of (x plus 1). Specifically,
\({\rm log1p}(\pm 0)\) returns \(\pm 0\)
\({\rm log1p}(-1)\) returns \(-\infty\)
\({\rm log1p}(x)\) returns NaN, if \(x \lt -1\).
\({\rm log1p}(\pm \infty)\) returns \(\pm \infty\)

Parameters:

x - a double value representing the argument.

Returns:

a double value representing log(1+x).

sinh

public static double sinh(double x)

Returns the hyperbolic sine of its argument. Specifically,
\({\rm sinh}(\pm 0)\) returns \(\pm 0\)
\({\rm sinh}(\pm \infty)\) returns \(\pm \infty\)

Parameters:

x - a double value representing the argument.

Returns:

a double value representing the hyperbolic sine of x.

cosh

public static double cosh(double x)

Returns the hyperbolic cosine of its argument. Specifically,
\({\rm cosh}(\pm 0)\) returns 1.
\({\rm cosh}(\pm \infty)\) returns \(+\infty\)

Parameters:

x - a double value representing the argument.

Returns:

a double value representing the hyperbolic cosine of x.

tanh

public static double tanh(double x)

Returns the hyperbolic tangent of its argument. Specifically,
\({\rm tanh}(\pm 0)\) returns \(\pm 0\)
\({\rm tanh}(\pm \infty)\) returns \(\pm 1\).

Parameters:

x - a double value representing the argument.

Returns:

a double value representing the hyperbolic tangent of x.

asinh

public static double asinh(double x)

Returns the inverse hyperbolic sine of its argument. Specifically,
\({\rm asinh}(\pm 0)\) returns \(\pm \infty\)
\({\rm asinh}(\pm \infty)\) returns \(\pm \infty\)

Parameters:

x - a double value representing the argument.

Returns:

a double value representing the number whose hyperbolic sine is x.

acosh

public static double acosh(double x)

Returns the inverse hyperbolic cosine of its argument. Specifically,
acosh(1) returns +0
\({\rm acosh}(\pm \infty)\) returns \(+\infty\)
\({\rm acosh}(x)\) returns NaN, if \(|x| \lt 1\).

Parameters:

x - a double value representing the argument.

Returns:

a double value representing the number whose hyperbolic cosine is x.

atanh

public static double atanh(double x)

Returns the inverse hyperbolic tangent of its argument. Specifically,
\({\rm atanh}(\pm 0)\) returns \(\pm 0\)
\({\rm atanh}(\pm 1)\) returns \(+\infty\)
atanh(x) returns NaN, if \(|x| \gt 1\).

Parameters:

x - a double value representing the argument.

Returns:

a double value representing the number whose hyperbolic tangent is x.