document.write( "Question 412786: x^2=16y i need help finding the directrix. \n" ); document.write( "

Algebra.Com's Answer #289927 by lwsshak3(11628) $\"\"$ $\"About$

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The standard form to use is (x-h)^2=4p(y-k), with (h,k) being the (x,y) coordinates of the vertex, and p the distance from vertex to focus and vertex to directrix in the other direction on the axis of symmetry. For the given equation, x^2=16y,it is a parabola that opens upwards,the vertex is at (0,0),axis of symmetry is x=0, and 4p=16 or p=4.\r
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