jn(3M)

NAME

     j0, j1, jn - Bessel functions of the first kind

SYNOPSIS

     cc [ flag ... ] file ... -lm [ library ... ]
     #include <math.h>

     double j0(double x);

     double j1(double x);

     double jn(int n, double x);

DESCRIPTION

     The j0(), j1() and jn() functions compute  Bessel  functions
     of x of the first kind of orders 0, 1 and n respectively.

RETURN VALUES

     Upon successful completion, j0(), j1() and jn()  return  the
     relevant Bessel value of x of the first kind.

     If the x argument is too large in magnitude, 0  is  returned
     and errno may be set to ERANGE.

     If x is NaN, NaN is returned.

     For exceptional cases, matherr(3M) tabulates the  values  to
     be returned as dictated by Standards other than XPG4.

ERRORS

     The j0(), j1() and jn() functions may fail if:

     ERANGE
           The value of x was too large in magnitude.

USAGE

     An application wishing to check for error situations  should
     set  errno  to 0 before calling j0(), j1() or jn(). If errno
     is non-zero on return, or the return value is NaN, an  error
     has occurred.

ATTRIBUTES

     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|

SEE ALSO

     isnan(3M), matherr(3M), y0(3M), attributes(5), standards(5)