Posted by dxli on Apr 11, 2012; 12:36pm
URL: https://forum.librecad.org/Tangent-arcs-circles-or-ellips-tp5604952p5632693.html

Added to the master branch, a solver for general simultaneous quadratic equation sets of two. commit: https://github.com/LibreCAD/LibreCAD/commit/66eee790819e22362e7fd79bf64312fc93281217

LibreCAD already has a solver limited to handle ellipse related methods, while the newly added solver can handle general equation sets of (x, y) in the form of:

 ma000 x^2 + ma001 xy + ma011 y^2 + mb00 x + mb01 y + mc0 =0
 ma100 x^2 + ma101 xy + ma111 y^2 + mb10 x + mb11 y + mc1 =0

The solver is based on algebraic methods relying on LibreCAD's own quartic equation solver.