Node: Solving Ellipses, Next: Rectangles for Ellipses, Previous: Ellipse Intersections, Up: Ellipse Reference
real_pair solve (char axis_unknown, real known)  const function 
Returns two possible values for either the horizontal or vertical
coordinate. This function assumes that the Ellipse lies in a major
plane with center at the origin. Code that calls it must ensure
that these conditions are fulfilled.

real_triple get_coefficients (real Slope, real v_intercept)  const function 
Let x and y stand for the x and ycoordinates of a point on an
ellipse in the xy plane, a for half of the horizontal axis
( Further, let y = mx + i be the equation of a line in the xy plane, where m is the slope and i the yintercept. This function returns the coefficients of the quadratic equation that results from replacing y with mx + i in the equation for the ellipse x^2/a^2 + y^2/b^2 = 1namely x^2/a^2 + (mx + i)^2/b^2  1 = 0 == (b^2x + a^2m^2)x^2 + 2a^2imx + (a^2i^2  a^2b^2) = 0.The coefficients are returned in the real_triple in the order
one would expect: r.first is the coefficient of x^2, r.second of
x and r.third of the constant term
(x^0 == 1).
