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)