bessel(3M)

NAME
     j0, j1, jn, y0, y1, yn, j0l, j1l, jnl, y0l, y1l, ynl - 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);

     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);

DESCRIPTION
     j0 and j1 return Bessel functions of x of the first kind of orders zero
     and one, respectively.  jn returns the Bessel function of x of the first
     kind of order n.  j0l, j1l, and jnl are the long double versions of these
     functions.

     y0 and y1 return Bessel functions of x of the second kind of orders zero
     and one, respectively.  yn returns the Bessel function of x of the second
     kind of order n.  The value of x must be positive.  y0l, y1l, and ynl are
     the long double versions of these functions.

DIAGNOSTICS
     In the diagnostics below, functions in the standard math library libm.a,
     are referred to as -lm versions, those in math library libmx.a are
     referred to as -lmx versions, and those in the the BSD math library
     libm43.a are referred to as -lm43 versions.  The -lm and -lmx versions
     always return the default Quiet NaN and set errno to EDOM when a NaN is
     used as an argument.  A NaN argument usually causes the -lm43 versions to
     return the same argument.  The -lm43 versions never set errno.
     The value of HUGE_VAL is IEEE Infinity.

     If the value of x is zero, y0, y1 and yn return the value -HUGE_VAL.  The
     -lm and -lmx versions also set errno to ERANGE.

     Negative values of x cause y0, y1 and yn to return the default quiet NaN.
     The -lm and -lmx versions also set errno to EDOM.

     Values of x too large cause y0, y1 and yn to return zero.  The -lm and
     -lmx versions also set errno to ERANGE.

     Values of x too large in magnitude cause j0, j1 and jn to return zero.
     The -lm and -lmx versions also set errno to ERANGE.

SEE ALSO
     math(3M), matherr(3M)