Solving equations 1 and 4 together,
5: (D*x+E*y)/2+F=0, a line not a tangent-point solution.
Rearranging by writing y as a function of x,
5: y=-(x*D/E+2*F/E) and y*y=((D*D/(E*E))*x*x+2*D*F/(E*E)*x+4*F*F/(E*E)
Substituting into the ellipse equation 1,
6...
How do I find the two tangent points of two lines from (0,0) to an ellipse?
We have 2 equations, a general ellipse and it differentiated:
1: A*x*x+B*x*y+C*y*y+D*x+E*y+F=0 is an ellipse if B*B-4*A*C<0.
Differentiating, 2: 2*A*x+B*x*dy/dx+B*y+2*C*y*dy/dx+D+E*dy/dx=0.
If F<0, ellipse not...