#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); float j0f(float x); float j1f(float x); float jnf(int n, float x); float y0f(float x); float y1f(float x); float ynf(int n, float x); long double j0l(long double x); long double j1l(long double x); long double jnl(int n, long double x); long double y0l(long double x); long double y1l(long double x); long double ynl(int n, long double x);
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 second 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.
The j0f() etc. and j0l() etc. functions are versions that take and return float and long double values, respectively.