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.\"     from: @(#)j0.3	6.7 (Berkeley) 4/19/91
.\" $FreeBSD: src/lib/msun/man/j0.3,v 1.8.2.3 2001/12/17 10:08:36 ru Exp $
.\" $DragonFly: src/lib/msun/man/Attic/j0.3,v 1.2 2003/06/17 04:26:52 dillon Exp $
.\"
.Dd April 19, 1991
.Dt J0 3
.Os
.Sh NAME
.Nm j0 ,
.Nm j0f ,
.Nm j1 ,
.Nm j1f ,
.Nm jn ,
.Nm jnf ,
.Nm y0 ,
.Nm y0f ,
.Nm y1 ,
.Nm y1f ,
.Nm yn ,
.Nm ynf
.Nd Bessel functions of first and second kind
.Sh LIBRARY
.Lb libm
.Sh SYNOPSIS
.In math.h
.Ft double
.Fn j0 "double x"
.Ft float
.Fn j0f "float x"
.Ft double
.Fn j1 "double x"
.Ft float
.Fn j1f "float x"
.Ft double
.Fn jn "int n" "double x"
.Ft float
.Fn jnf "int n" "float x"
.Ft double
.Fn y0 "double x"
.Ft float
.Fn y0f "float x"
.Ft double
.Fn y1 "double x"
.Ft float
.Fn y1f "float x"
.Ft double
.Fn yn "int n" "double x"
.Ft float
.Fn ynf "int n" "float x"
.Sh DESCRIPTION
The functions
.Fn j0 ,
.Fn j0f ,
.Fn j1
and
.Fn j1f
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 functions
.Fn jn
and
.Fn jnf
compute the
.Em Bessel function of the first kind of the integer
.Em order
.Fa n
for the real value
.Fa x .
.Pp
The functions
.Fn y0 ,
.Fn y0f ,
.Fn y1 ,
and
.Fn y1f
compute the linearly independent
.Em Bessel function of the second kind of the order
0 and the
.Em order
1, respectively,
for the
positive
.Em real
value
.Fa x ;
the functions
.Fn yn
and
.Fn ynf
compute the
.Em Bessel function of the second kind for the integer
.Em order
.Fa n
for the positive
.Em real
value
.Fa x .
.Sh RETURN VALUES
If these functions are successful,
the computed value is returned.
On the
.Tn VAX
and
.Tn Tahoe
architectures,
for the Bessel functions of the second kind,
a negative
or zero
.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
.Sh HISTORY
This set of functions
appeared in
.At v7 .