J0(3) Linux Programmer's Manual J0(3) NAME j0, j1, jn, y0, y1, yn - Bessel functions SYNOPSIS #include <math.h> double j0(double x); double j1(double x); double jn(int n, double x); double y0(double x); double y1(double x); double yn(int n, double x); 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 y0() and y1() functions return Bessel functions of x of the second kind of orders 0 and 1, respectively. The yn() function returns the Bessel function of x of the sec- ond kind of order n. For the functions y0(), y1() and yn(), the value of x must be positive. For negative values of x, these functions return -HUGE_VAL. CONFORMING TO SVID 3, BSD 4.3 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. June 26, 1993 1