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(Polar Equations) Finding the equation of a ellipse and hyperbola - Printable Version +- Southperry.net (https://www.southperry.net) +-- Forum: Social (https://www.southperry.net/forumdisplay.php?fid=14) +--- Forum: Rubik's Cube (https://www.southperry.net/forumdisplay.php?fid=58) +--- Thread: (Polar Equations) Finding the equation of a ellipse and hyperbola (/showthread.php?tid=39830) |
(Polar Equations) Finding the equation of a ellipse and hyperbola - Imagine - 2011-03-27 1. Given the vertices (2,0) and (10, pi), find the equation of the ellipse. 2. Given the vertices (1, 3pi/2) and (9, 3pi/2), find the equation of the hyperbola. I seriously have no clue on what do to for these type of problems. (Polar Equations) Finding the equation of a ellipse and hyperbola - Shidoshi - 2011-03-27 ellipsis should probably be something like this: (sin(theta)/A)²+(cos(theta)/B)²=1/r² With A and B being the maximum distance they go. from the cartesian equation: (x/A)²+(y/B)²=1 But I think with the vertices you should build the equations from the ellipsis definition: "A cord of fixed length tied to the two vertices will pass by all points of an ellipsis when held stretched" (Polar Equations) Finding the equation of a ellipse and hyperbola - 2147483647 - 2011-03-27
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-------Edit: Crap. I didn't see that this is in polar form. That drastically simplifies things. For polar equation, the origin is always one of the focal points. The general equation for a horizontal ellipse that has the center at π is: r(θ = a*(1-e^2)/(1+e*cos(θ )The general equation for a vertical hyperbola that has center at 3π/2 is: r(θ = a*(e^2-1)/(1+e*sin(θ )e is the eccentricity. e = c/a where c is the distance from the center of the conic to the focus and a is the radius along the longer axis This is the same a as the a in the equation. Plug and chug. I wasted so much time doing it in rectangular. Lol. (Polar Equations) Finding the equation of a ellipse and hyperbola - madanthony - 2011-03-28 If you want to take an hour or two and really learn it, I bet Khan can help. http://www.khanacademy.org/video/introduction-to-conic-sections?playlist=Algebra That's the starting point, and there are about 10 videos of relevance following that. If you make an account, there are exercises as well. |