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 8.2 (Berkeley) 04/19/94 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 positive 64.Em integer 65value 66.Fa x 67(expressed as a double); 68the function 69.Fn yn 70computes the 71.Em Bessel function of the second kind for the integer order 72.Fa n 73for the positive 74.Em integer 75value 76.Fa x 77(expressed as a double). 78.Sh RETURN VALUES 79If these functions are successful, 80the computed value is returned. On the 81.Tn VAX 82and 83.Tn Tahoe 84architectures, 85a negative 86.Fa x 87value 88results in an error; the global 89variable 90.Va errno 91is set to 92.Er EDOM 93and a reserve operand fault is generated. 94.Sh SEE ALSO 95.Xr math 3 , 96.Xr infnan 3 97.Sh HISTORY 98A set of these functions 99function appeared in 100.At v7 . 101