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document.write( "There are 2 answers, because the parabola can open right or\r\n" );
document.write( "it can open left.\r\n" );
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document.write( "
\r\n" );
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document.write( "The equation of a parabola that faces left or right is\r\n" );
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\r\n" );
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document.write( "Where (h,k) is the vertex\r\n" );
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document.write( "If p is taken positive it opens to the right, if\r\n" );
document.write( "p is taken negative, it opens to the left.\r\n" );
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document.write( "The latus rectum is 4p. That's the green line, which\r\n" );
document.write( "is 6 units in length. I'll just do the one that opens\r\n" );
document.write( "to the right. So 4p = +6, taking it positive.\r\n" );
document.write( " p = 
\r\n" );
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document.write( "The distance p is the distance from the vertex to the \r\n" );
document.write( "focus. So the vertex of the first parabola is \r\n" );
document.write( "or 
units left of the focus (-2,-1), and\r\n" );
document.write( "that point is\r\n" );
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document.write( "(h,k) = 
\r\n" );
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document.write( "So the equation of the first parabola above is\r\n" );
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document.write( "
\r\n" );
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document.write( "
\r\n" );
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document.write( "You can simplify that if your teacher wants you to.\r\n" );
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document.write( "Now you find the equation of the parabola that opens to\r\n" );
document.write( "the left.\r\n" );
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document.write( "Edwin
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document.write( "![\"\"](\"/images/stars/stars-13.gif\")
