document.write( "Question 624991: please help me solve this equation (Write the equation of a parabola with a vertex at (0, 0) and a directrix y = -1 \n" ); document.write( "

Algebra.Com's Answer #393256 by jsmallt9(3758) $\"\"$ $\"About$

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With a vertex of (0, 0) and a directrix of y = -1, the directrix is below the vertex. This makes the parabola a parabola that opens upward (like a \"u\"). One form for the equation of these parabolas is:
\n" ); document.write( " $\"%28x-h%29%5E2+=+4p%28y-k%29\"$
\n" ); document.write( "where \"h\" and \"k\" are the x and y coordinates of the vertex and \"p\" is the distance from the vertex to the focus (or to the directrix). We are given that the vertex is (0, 0) so both h and k are zeros. And we can calculate \"p\". The distance from your vertex (0, 0) to the directrix is 1. So p = 1. Inserting these values into the standard form we get:
\n" ); document.write( " $\"%28x-0%29%5E2+=+4%281%29%28y-0%29\"$
\n" ); document.write( "which simplifies to:
\n" ); document.write( " $\"x%5E2+=+4y\"$ \n" ); document.write( "

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