bessel(S)                      6 January 1993                      bessel(S)


 Name

    bessel: j0, j1, jn, y0, y1, yn - bessel functions

 Syntax


    cc  . . .  -lm


    #include  <math.h>

    double j0 (x)
    double x;

    double j1 (x)
    double x;

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

    double y0 (x)
    double x;

    double y1 (x)
    double x;

    double yn (n, x)
    int n;
    double x;


 Description

    j0 and j1 return Bessel functions of x of the first kind of orders 0 and
    1 respectively.  jn returns the Bessel function of x of the first kind of
    order n.

    y0 and y1 return Bessel functions of x of the second kind of orders 0 and
    1 respectively.  yn returns the Bessel function of x of the second kind
    of order n.  The value of x must be positive.

 Diagnostics

    Non-positive arguments cause y0, y1, and yn to return the value
    -HUGEiVAL and to set errno to EDOM.  In addition, a message indicating
    DOMAIN error is printed on the standard error output.

    Arguments too large in magnitude cause j0, j1, y0, and y1 to return zero
    and to set errno to ERANGE.  In addition, a message indicating TLOSS
    error is printed on the standard error output.

    These error-handling procedures may be changed with the function
    matherr(S).

 See also

    matherr(S)

 Standards conformance

    j0, j1, jn, y0, y1 and yn are conformant with:
    AT&T SVID Issue 2;
    and X/Open Portability Guide, Issue 3, 1989.