document.write( "Question 835350: Hey. My name is Anne. Nice to meet your lovely self. ^_^
\n" ); document.write( "Conics confuse me completely. Right now my class is on ellipses. So my question is how do I find an equation of an ellipse? It gave me a graph, and a couple points. The major axis is vertical, and the vertex is (0,10) and (0,-10). The focus is at (0,8) and (0,-8).
\n" ); document.write( "I know there's some kind of equation to put these numbers in, but somehow that did not end up in my notes! :(
\n" ); document.write( "While I'm asking, how would I do this when the major axis is horizontal? (I know that's asking 2 questions. I understand if you can't, or won't answer that one. I just need the equation.)
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Algebra.Com's Answer #503463 by lwsshak3(11628)\"\" \"About 
You can put this solution on YOUR website!
How do I find an equation of an ellipse? It gave me a graph, and a couple points. The major axis is vertical, and the vertex is (0,10) and (0,-10). The focus is at (0,8) and (0,-8).
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\n" ); document.write( "When trying to find the equation for a given ellipse, you must first determine whether it has a vertical or horizontal major axis.
\n" ); document.write( "..
\n" ); document.write( "If major axis is vertical,
\n" ); document.write( "Standard form of equation for the ellipse:
\n" ); document.write( "\"%28x-h%29%5E2%2Fb%5E2%2B%28y-k%29%5E2%2Fa%5E2=1\", a>b,(h,k)=(x,y) coordinates of center
\n" ); document.write( "..
\n" ); document.write( "If major axis is horizontal,
\n" ); document.write( "Standard form of equation for the ellipse:
\n" ); document.write( "\"%28x-h%29%5E2%2Fa%5E2%2B%28y-k%29%5E2%2Fb%5E2=1\", a>b,(h,k)=(x,y) coordinates of center
\n" ); document.write( "(notice the only change is a^2 and b^2 swapping places)
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\n" ); document.write( "Now, for your given ellipse problem:
\n" ); document.write( "Gleaned from the 2 given points of the vertex,
\n" ); document.write( "x-coordinate of center=0
\n" ); document.write( "y-coordinate of center=0
\n" ); document.write( "so,center(0,0)
\n" ); document.write( "a=10(given distance from center to vertices on the vertical major axis)
\n" ); document.write( "a^2=100
\n" ); document.write( "..
\n" ); document.write( "c=8(given distance from center to foci on the vertical major axis)
\n" ); document.write( "c^2=64
\n" ); document.write( "..
\n" ); document.write( "c^2=a^2-b^2
\n" ); document.write( "b^2=a^2-c^2=100-64=36
\n" ); document.write( "b=√36=6
\n" ); document.write( "..
\n" ); document.write( "equation:
\n" ); document.write( "\"%28x-0%29%5E2%2Fb%5E2%2B%28y-0%29%5E2%2Fa%5E2=1\"
\n" ); document.write( "\"x%5E2%2F36%2By%5E2%2F100=1\"\r
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