J0(3)

NAME
j0, j0f, j1, j1f, jn, jnf, y0, y0f, y1, y1f, yn, ynf - Bessel functions of first and second kind

LIBRARY
libm

SYNOPSIS
#include <math.h>
double
j0(double x);
float
j0f(float x);
double
j1(double x);
float
j1f(float x);
double
jn(int n, double x);
float
jnf(int n, float x);
double
y0(double x);
float
y0f(float x);
double
y1(double x);
float
y1f(float x);
double
yn(int n, double x);
float
ynf(int n, float x);

DESCRIPTION
The functions j0(), j0f(), j1(), and j1f() compute the Bessel function of the first kind of orders 0 and 1 for the real value x; the functions jn() and jnf() compute the Bessel function of the first kind of the integer order n for the real value x.

The functions y0(), y0f(), y1(), and y1f() compute the linearly independent Bessel function of the second kind of orders 0 and 1 for the positive real value x; the functions yn() and ynf() compute the Bessel function of the second kind for the integer order n for the positive real value x.

RETURN VALUES
These routines return values of their respective Bessel functions. For large positive inputs, they may underflow and return 0.

The following applies to y0(), y0f(), y1(), y1f(), yn(), and ynf(). If x is negative, including -, these routines will generate an invalid exception and return . If x is 0, these routines will generate a divide-by-zero exception and return -. If x is a sufficiently small positive number, then y1(), y1f(), yn(), and ynf() will generate an overflow exception and return -.

SEE ALSO
math(3)

STANDARDS
The j0(), j1(), jn(), y0(), y1(), and yn() functions conform to p1003.1-2001. The float versions are extensions.

HISTORY
This set of functions appeared in AT&T UNIX.