document.write( "Question 1181020: Dear Sir/Ma'am\r
\n" ); document.write( "\n" ); document.write( "Please Help me solve this problem.\r
\n" ); document.write( "\n" ); document.write( "Find the equation if the Ellipse with center at (2,3), Vertices at (2,9) and (2,-3) and Eccentricity of 2/3/ Identify the parts of the Ellipse and sketch the graph.\r
\n" ); document.write( "\n" ); document.write( "Parts of the Ellipse
\n" ); document.write( "1. Center
\n" ); document.write( "2. Foci
\n" ); document.write( "3. Vertices V1, V2
\n" ); document.write( "4. Co Vertices B1, B2
\n" ); document.write( "5. Endpoints of Latus Rectum E1, E2, E3, E4
\n" ); document.write( "6. Directrices
\n" ); document.write( "7. Eccentricity
\n" ); document.write( "8. Length of LR
\n" ); document.write( "9. Length of Major Axis
\n" ); document.write( "10. Length of Minor Axis\r
\n" ); document.write( "\n" ); document.write( "Thank you and GOD Bless\r
\n" ); document.write( "\n" ); document.write( "Sincerely Yours,\r
\n" ); document.write( "\n" ); document.write( "Lorna\r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #810859 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
equation:\r
\n" ); document.write( "\n" ); document.write( "\"%28x-h%29%5E2%2Fa%5E2%2B%28y-k%29%5E2%2Fb%5E2=1\"\r
\n" ); document.write( "\n" ); document.write( "given:\r
\n" ); document.write( "\n" ); document.write( "center at (\"2\",\"3\")=>\"h=2\" and \"k=3\"\r
\n" ); document.write( "\n" ); document.write( "Vertices at (\"2\",\"9\") and (\"2\",\"-3\")
\n" ); document.write( "as you can see major axis is parallel to y-axis, so it is \"b\",the ellipse is vertical \r
\n" ); document.write( "\n" ); document.write( "and distance between vertices is \"2b=12\"
\n" ); document.write( "=>\"b=6\"\r
\n" ); document.write( "\n" ); document.write( "so far your equation is:\r
\n" ); document.write( "\n" ); document.write( "\"%28x-2%29%5E2%2Fa%5E2%2B%28y-3%29%5E2%2F6%5E2=1\"\r
\n" ); document.write( "\n" ); document.write( "given ccentricity of \"2%2F3\"
\n" ); document.write( "The eccentricity (e) of an ellipse is the ratio of the distance from the center to the foci (c) and the distance from the center to the vertices (b).\r
\n" ); document.write( "\n" ); document.write( "\"2%2F3=c%2Fb\"
\n" ); document.write( "\"2%2F3=c%2F6\"
\n" ); document.write( "\"c=%282%2F3%296\"
\n" ); document.write( "\"c=4\"\r
\n" ); document.write( "\n" ); document.write( "now find minor axis \"a\"
\n" ); document.write( "\"a=sqrt%286%5E2-4%5E2%29\"
\n" ); document.write( "\r
\n" ); document.write( "\n" ); document.write( "\"%28x-2%29%5E2%2F20%2B%28y-3%29%5E2%2F36=1\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "semimajor axis length : \"6\"
\n" ); document.write( "semiminor axis length: \"sqrt%2820%29\"\"4.5\"
\n" ); document.write( "major axis length : \"12\"
\n" ); document.write( "minor axis length: \"9\"\r
\n" ); document.write( "\n" ); document.write( "foci:
\n" ); document.write( "(\"h\", \"k%2Bc\" ), (\"h\", \"k-c\" )
\n" ); document.write( "=>(\"2\", \"3%2B4\" ), (\"2\", \"3-4\" )
\n" ); document.write( "=>(\"2\", \"7\" ), (\"2\", \"-1\" )\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "foci:
\n" ); document.write( "(\"h\", \"k-c\") , (\"h\", \"k%2Bc\")
\n" ); document.write( "(\"2\", \"3-4\") , (\"2\", \"3%2B4\")
\n" ); document.write( "(\"2\", \"-1\") , (\"2\", \"7\")\r
\n" ); document.write( "\n" ); document.write( "covertices:
\n" ); document.write( "(\"h+%2B+b\", \"k\") ,(\"h+-+b\", \"k\")
\n" ); document.write( "(\"2++%2B+sqrt%2820%29\", \"3\"), (\"2+-+sqrt%2820%29\", \"3\")
\n" ); document.write( "≈(\"6.5\", \"3\") , (\"-2.5\", \"3\")\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "eccentricity: \"2%2F3\"\r
\n" ); document.write( "\n" ); document.write( "directrices: since you have vertical ellipse, directrices are \"+k=3\" from each y coordinate of the vertices
\n" ); document.write( "\"y=9%2B+3=12\"
\n" ); document.write( "\"y=-3-3=-6\"
\n" ); document.write( "First directrix: \"y=-6\"\r
\n" ); document.write( "\n" ); document.write( "Second directrix: \"y=12\"\r
\n" ); document.write( "\n" ); document.write( "Endpoints of Latus Rectum
\n" ); document.write( "The chord of the ellipse through its one focus and perpendicular to the major axis (or parallel to the directrix) is called the latus rectum of the ellipse.\r
\n" ); document.write( "\n" ); document.write( "since foci is at: (\"2\", \"-1\") , (\"2\", \"7\")\r
\n" ); document.write( "\n" ); document.write( "first latus rectum: \"y=-1\"
\n" ); document.write( "substitute in ellipse formula and you get
\n" ); document.write( "\"x+=+-4%2F3\" or \"x+=+16%2F3\"\r
\n" ); document.write( "\n" ); document.write( "two Endpoints of Latus Rectum are
\n" ); document.write( "E1=\"-4%2F3\",\"-1\" and E1=\"16%2F3\",\"-1\"\r
\n" ); document.write( "\n" ); document.write( "second latus rectum: \"y=7+\"
\n" ); document.write( "\"x\" same as above\r
\n" ); document.write( "\n" ); document.write( "E3=\"-4%2F3\",\"7\" and E4=\"16%2F3\",\"7\"\r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "
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