document.write( "Question 984603: Find an equation of the parabola described then graph the parabola. Focus(-2,1); Vertex(-3,1) \n" ); document.write( "

Algebra.Com's Answer #605377 by josgarithmetic(39620) $\"\"$ $\"About$

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Knowing vertex and focus, you can find the directrix.; the distance between vertex and the focus is the same distance between the vertex and the nearest point on the directrix.\r
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\n" ); document.write( "\n" ); document.write( "The number p is the distance between the vertex and the focus. Knowing p and the vertex, you can write an equation for the parabola directly. \r
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\n" ); document.write( "\n" ); document.write( "Your parabola opens toward the left, so you will have a form like $\"4p%28y-h%29=-%28x-h%29%5E2\"$ .\r
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\n" ); document.write( "\n" ); document.write( "Either or both of these video presentations will help:\r
\n" ); document.write( "\n" ); document.write( "Equation of parabola, vertex at origin - Derivation
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\n" ); document.write( "Equation of parabola, vertex not at origin, focus and directrix given - general \n" ); document.write( "

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