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 nonstandard
       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 3.54 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/.

                                                   2010-09-20                                              J0(3)