1.\" Copyright (c) 1985, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)j0.3 8.1 (Berkeley) 06/04/93 7.\" 8.Dd 9.Dt J0 3 10.Os BSD 4 11.Sh NAME 12.Nm j0 , 13.Nm j1 , 14.Nm jn , 15.Nm y0 , 16.Nm y1 , 17.Nm yn 18.Nd bessel functions of first and second kind 19.Sh SYNOPSIS 20.Fd #include <math.h> 21.Ft double 22.Fn j0 "double x" 23.Ft double 24.Fn j1 "double x" 25.Ft double 26.Fn jn "int n" "double x" 27.Ft double 28.Fn y0 "double x" 29.Ft double 30.Fn y1 "double x" 31.Ft double 32.Fn yn "int n" "double x" 33.Sh DESCRIPTION 34The functions 35.Fn j0 36and 37.Fn j1 38compute the 39.Em Bessel function of the first kind of the order 400 and the 41.Em order 421, respectively, 43for the 44real value 45.Fa x ; 46the function 47.Fn jn 48computes the 49.Em Bessel function of the first kind of the integer order 50.Fa n 51for the real value 52.Fa x . 53.Pp 54The functions 55.Fn y0 56and 57.Fn y1 58compute the linearly independent 59.Em Bessel function of the second kind of the order 600 and the 61.Em order 621, respectively, 63for the 64postive 65.Em integer 66value 67.Fa x 68(expressed as a double); 69the function 70.Fn yn 71computes the 72.Em Bessel function of the second kind for the integer order 73.Fa n 74for the postive 75.Em integer 76value 77.Fa x 78(expressed as a double). 79.Sh RETURN VALUES 80If these functions are successful, 81the computed value is returned. On the 82.Tn VAX 83and 84.Tn Tahoe 85architectures, 86a negative 87.Fa x 88value 89results in an error; the global 90variable 91.Va errno 92is set to 93.Er EDOM 94and a reserve operand fault is generated. 95.Sh SEE ALSO 96.Xr math 3 , 97.Xr infnan 3 98.Sh HISTORY 99A set of these functions 100function appeared in 101.At v7 . 102