J0(3) BSD Programmer's Manual J0(3)

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

libm

**#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*);

The functions **j0**(), **j0f**(), **j1**() and **j1f**() compute the *Bessel function of*
*the first kind of the order* 0 and the *order* 1, respectively, for the real
value *x*; the functions **jn**() and **jnf**() compute the *Bessel function of the*
*first kind of the integer n* for the real value *x*.
The functions **y0**(), **y0f**(), **y1**() and **y1f**() compute the linearly indepen-
dent *Bessel function of the second kind of the order* 0 and the *order* 1,
respectively, for the positive *integer* value *x* (expressed as a double);
the functions **yn**() and **ynf**() compute the *Bessel function of the second*
*kind for the integer n* for the positive *integer* value *x* (expressed as a
double).

If these functions are successful, the computed value is returned, other-
wise the global variable *errno* is set to EDOM and a reserve operand fault
is generated.

math(3)

This set of functions appeared in Version 7 AT&T UNIX.
MirBSD #10-current April 19, 1991 1