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

NAME
       j0,  j0f,  j0l,	j1,  j1f,  j1l, jn, jnf, jnl - Bessel functions of the
       first kind

SYNOPSIS
       #include <math.h>

       double j0(double x);
       double j1(double x);
       double jn(int n, double x);

       float j0f(float x);
       float j1f(float x);
       float jnf(int n, float x);

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

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       j0(), j1(), jn(): _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE
       j0f(), j0l(), j1f(), j1l(), jnf(), jnl(): _SVID_SOURCE || _BSD_SOURCE
       || _XOPEN_SOURCE >= 600

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

RETURN VALUE
       On success, these functions return the appropriate Bessel value of  the
       first kind for x.

       If x is a NaN, a NaN is returned.

       If x is too large in magnitude, or the result underflows, a range error
       occurs, and the return value is 0.

ERRORS
       See math_error(7) for information on how to determine whether an	 error
       has occurred when calling these functions.

       The following errors can occur:

       Range error: result underflow, or x is too large in magnitude
	      errno is set to ERANGE.

       These functions do not raise exceptions for fetestexcept(3).

CONFORMING TO
       The  functions  returning double conform to SVr4, 4.3BSD, POSIX.1-2001.
       The others are non-standard functions that also exist on the BSDs.

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.

SEE ALSO
       y0(3)

COLOPHON
       This  page  is  part of release 3.23 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

				  2008-08-05				 J0(3)

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