1.\" Copyright (c) 1985, 1991 Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)j0.3 6.7 (Berkeley) 4/19/91 33.\" 34.Dd April 19, 1991 35.Dt J0 3 36.Os BSD 4 37.Sh NAME 38.Nm j0 , 39.Nm j1 , 40.Nm jn , 41.Nm y0 , 42.Nm y1 , 43.Nm yn 44.Nd bessel functions of first and second kind 45.Sh SYNOPSIS 46.Fd #include <math.h> 47.Ft double 48.Fn j0 "double x" 49.Ft double 50.Fn j1 "double x" 51.Ft double 52.Fn jn "int n" "double x" 53.Ft double 54.Fn y0 "double x" 55.Ft double 56.Fn y1 "double x" 57.Ft double 58.Fn yn "int n" "double x" 59.Sh DESCRIPTION 60The functions 61.Fn j0 62and 63.Fn j1 64compute the 65.Em Bessel function of the first kind of the order 660 and the 67.Em order 681, respectively, 69for the 70real value 71.Fa x ; 72the function 73.Fn jn 74computes the 75.Em Bessel function of the first kind of the integer order 76.Fa n 77for the real value 78.Fa x . 79.Pp 80The functions 81.Fn y0 82and 83.Fn y1 84compute the linearly independent 85.Em Bessel function of the second kind of the order 860 and the 87.Em order 881, respectively, 89for the 90postive 91.Em integer 92value 93.Fa x 94(expressed as a double); 95the function 96.Fn yn 97computes the 98.Em Bessel function of the second kind for the integer order 99.Fa n 100for the postive 101.Em integer 102value 103.Fa x 104(expressed as a double). 105.Sh RETURN VALUES 106If these functions are successful, 107the computed value is returned. On the 108.Tn VAX 109and 110.Tn Tahoe 111architectures, 112a negative 113.Fa x 114value 115results in an error; the global 116variable 117.Va errno 118is set to 119.Er EDOM 120and a reserve operand fault is generated. 121.Sh SEE ALSO 122.Xr math 3 , 123.Xr infnan 3 124.Sh HISTORY 125A set of these functions 126function appeared in 127.At v7 . 128