document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=675774>Question 675774</A>: <I><SPAN STYLE=\"word-break: break-all;\"> v=(4,2) Directrix : y=5  (this is the given information)\r<BR>\n" );
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document.write( "I get focus is 4,1<BR>\n" );
document.write( "and this is the formula I come up with <BR>\n" );
document.write( "(x-4)^2=12(y-2)<BR>\n" );
document.write( "y=1/12(x-4)^2+2\r<BR>\n" );
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document.write( "BUT.........When I put this answer into wolfframAlpha to check it I get the focus and the directrix flipped!  Does anyone know why that happens?<BR>\n" );
document.write( "it gives the focus as 4,5 and the directrix as -1y\r<BR>\n" );
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document.write( "Am I doing something wrong?  how does the equation know show where the focus and the directrix are located? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #420253 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=420253\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> v=(4,2) Directrix : y=5<BR>\n" );
document.write( "This is a parabola that opens downwards.<BR>\n" );
document.write( "Its standard form of equation: (x-h)^2=-4p(y-k), (h,k)=(x,y) coordinates of vertex<BR>\n" );
document.write( "given coordinates of the vertex:(4,2)<BR>\n" );
document.write( "axis of symmetry: x=2<BR>\n" );
document.write( "focus:(4,-1) (3 units below vertex on the axis of symmetry)<BR>\n" );
document.write( "p=3 (distance from directrix to vertex on the axis of symmetry)<BR>\n" );
document.write( "4p=12<BR>\n" );
document.write( "equation:<BR>\n" );
document.write( "(x-4)^2=-12(y-2)\r<BR>\n" );
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document.write( "note:The directrix is always located on the opposite side the parabola is facing and the focus is on the side the parabola is facing, both p-distance from the vertex on the axis of symmetry. </SPAN>\n" );
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