1 %% Copyright (c) 2011, INRA
2 %% 2004-2011, David Legland <david.legland@grignon.inra.fr>
3 %% 2011 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
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35 %% @deftypefn {Function File} {@var{line} = } radicalAxis (@var{circle1}, @var{circle2})
36 %% Compute the radical axis (or radical line) of 2 circles
38 %% L = radicalAxis(C1, C2)
39 %% Computes the radical axis of 2 circles.
44 %% L = radicalAxis(C1, C2);
45 %% hold on; axis equal;axis([0 100 0 100]);
46 %% drawCircle(C1);drawCircle(C2);drawLine(L);
49 %% http://mathworld.wolfram.com/RadicalLine.html
50 %% http://en.wikipedia.org/wiki/Radical_axis
52 %% @seealso{lines2d, circles2d, createCircle}
56 function line = radicalAxis(circle1, circle2)
58 % extract circles parameters
66 % distance between each couple of centers
67 dist = sqrt((x2-x1).^2 + (y2-y1).^2);
69 % relative position of intersection point of
70 % the radical line with the line joining circle centers
71 d = (dist.^2 + r1.^2 - r2.^2) * .5 ./ dist;
73 % compute angle of radical axis
74 angle = lineAngle(createLine([x1 y1], [x2 y2]));
78 % parameters of the line
84 % concatenate into one structure