Intersection between rotated & translated ellipse and line

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SUMMARY

This discussion focuses on finding the intersection points between a rotated and translated ellipse and a line segment defined by two points (x1, y1) and (x2, y2). The user initially attempted to use Wolfram Alpha for solving the equations but found it impractical for the rotated ellipse. Two suggested methods include substituting one variable from the line equation into the ellipse equation or transforming the ellipse into standard form and applying the same transformation to the line before solving the system of equations.

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piercazzo
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I have a rotated ellipse, not centered at the origin, defined by x,y,a,b and angle.
Then I have a segment defined by two points x1,y1 and x2,y2
Is there a quick way to find the intersection points?

I used wolfram alpha equation solver, I tried to insert the equation of a line into the one of a standard non rotated, non translated ellipse,

10how40.gif


and resolving for x this is the result

15qw704.png


which is nice.

Then I took the equation of a rotated and translated ellipse

vngnwi.png


and this is the result

2rnzx1h.png

6p5bat.png


Which is obviously impractical, can anyone suggest a different method?
 
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Do it by hand rather than use the calculator.
You can either -
1. Solve for one variable in the line equation and sub into the ellipse equation - solve for the other coordinate ... you know: as usual.

2. transform the ellipse into standard form, apply the same transformation to the line, find solutions for the transformed system, apply the inverse transformation to the solution.
 

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