АРКТАНГЕНС
function [ n_data, x, fx ] = arctan_values ( n_data )
%*****************************************************************************80
%
%% ARCTAN_VALUES returns some values of the arc tangent function.
%
% Discussion:
%
% In Mathematica, the function can be evaluated by:
%
% ArcTan[x]
%
% Licensing:
%
% This code is distributed under the GNU LGPL license.
%
% Modified:
%
% 12 June 2007
%
% Author:
%
% John Burkardt
%
% Reference:
%
% Milton Abramowitz, Irene Stegun,
% Handbook of Mathematical Functions,
% National Bureau of Standards, 1964,
% ISBN: 0-486-61272-4,
% LC: QA47.A34.
%
% Stephen Wolfram,
% The Mathematica Book,
% Fourth Edition,
% Cambridge University Press, 1999,
% ISBN: 0-521-64314-7,
% LC: QA76.95.W65.
%
% Parameters:
%
% Input/output, integer N_DATA. The user sets N_DATA to 0 before the
% first call. On each call, the routine increments N_DATA by 1, and
% returns the corresponding data; when there is no more data, the
% output value of N_DATA will be 0 again.
%
% Output, real X, the argument of the function.
%
% Output, real FX, the value of the function.
%
n_max = 11;
fx_vec = [ ...
0.00000000000000000000, ...
0.24497866312686415417, ...
0.32175055439664219340, ...
0.46364760900080611621, ...
0.78539816339744830962, ...
1.1071487177940905030, ...
1.2490457723982544258, ...
1.3258176636680324651, ...
1.3734007669450158609, ...
1.4711276743037345919, ...
1.5208379310729538578 ];
x_vec = [ ...
0.00000000000000000000, ...
0.25000000000000000000, ...
0.33333333333333333333, ...
0.50000000000000000000, ...
1.0000000000000000000, ...
2.0000000000000000000, ...
3.0000000000000000000, ...
4.0000000000000000000, ...
5.0000000000000000000, ...
10.000000000000000000, ...
20.000000000000000000 ];
if ( n_data < 0 )
n_data = 0;
end
n_data = n_data + 1;
if ( n_max < n_data )
n_data = 0;
x = 0.0;
fx = 0.0;
else
x = x_vec(n_data);
fx = fx_vec(n_data);
end
return
end
