.\" Copyright (c) 1985, 1991 Regents of the University of California.
.\" All rights reserved.
.\"
.\" %sccs.include.redist.man%
.\"
.\"     @(#)j0.3	6.7 (Berkeley) 04/19/91
.\"
.Dd 
.Dt J0 3
.Os BSD 4
.Sh NAME
.Nm j0 ,
.Nm j1 ,
.Nm jn ,
.Nm y0 ,
.Nm y1 ,
.Nm yn
.Nd bessel functions of first and second kind
.Sh SYNOPSIS
.Fd #include <math.h>
.Ft double
.Fn j0 "double x"
.Ft double
.Fn j1 "double x"
.Ft double
.Fn jn "int n" "double x"
.Ft double
.Fn y0 "double x"
.Ft double
.Fn y1 "double x"
.Ft double
.Fn yn "int n" "double x"
.Sh DESCRIPTION
The functions
.Fn j0
and
.Fn j1
compute the
.Em Bessel function of the first kind of the order
0 and the
.Em order
1, respectively,
for the
real value
.Fa x ;
the function
.Fn jn
computes the
.Em Bessel function of the first kind of the integer order
.Fa n
for the real value
.Fa x .
.Pp
The functions
.Fn y0
and
.Fn y1
compute the linearly independent
.Em Bessel function of the second kind of the order
0 and the
.Em order
1, respectively,
for the
postive
.Em integer
value
.Fa x
(expressed as a double);
the function
.Fn yn
computes the
.Em Bessel function of the second kind for the integer order
.Fa n
for the postive 
.Em integer
value
.Fa x
(expressed as a double).
.Sh RETURN VALUES
If these functions are successful,
the computed value is returned. On the
.Tn VAX
and
.Tn Tahoe
architectures,
a negative
.Fa x
value
results in an error; the global
variable
.Va errno
is set to
.Er EDOM
and a reserve operand fault is generated.
.Sh SEE ALSO
.Xr math 3 ,
.Xr infnan 3
.Sh HISTORY
A set of these functions
function appeared in
.At v7 .