# yn

```J0(3)                      Linux Programmer's Manual                     J0(3)

NAME
j0,  j0f,  j0l, j1, j1f, j1l, jn, jnf, jnl, y0, y0f, y0l, y1, y1f, y1l,
yn, ynf, ynl - Bessel functions

SYNOPSIS
#include <math.h>

double j0(double x);
double j1(double x);
double jn(int n, double x);
double y0(double x);
double y1(double x);
double yn(int n, double x);

float j0f(float x);
float j1f(float x);
float jnf(int n, float x);
float y0f(float x);
float y1f(float x);
float ynf(int n, float x);

long double j0l(long double x);
long double j1l(long double x);
long double jnl(int n, long double x);
long double y0l(long double x);
long double y1l(long double x);
long double ynl(int n, long double x);

DESCRIPTION
The j0() and j1() functions return Bessel functions of x of  the  first
kind  of  orders  0 and 1, respectively.  The jn() function returns the
Bessel function of x of the first kind of order n.

The y0() and y1() functions return Bessel functions of x of the  second
kind  of  orders  0 and 1, respectively.  The yn() function returns the
Bessel function of x of the second kind of order n.

For the functions y0(), y1() and yn(), the value of x must be positive.
For negative values of x, these functions return -HUGE_VAL.

The  j0f()  etc.  and  j0l()  etc. functions are versions that take and
return float and long double values, respectively.

CONFORMING TO
The functions returning double conform to SVID 3, BSD 4.3, XPG4,  POSIX
1003.1-2001. The other functions exist by analogy, and exist on several
platforms.

BUGS
There are errors of up to 2e-16 in the values returned  by  j0(),  j1()
and jn() for values of x between -8 and 8.

2002-08-25                             J0(3)
```