document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=801045>Question 801045</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hi! I have a problem that asks: \"Find the focus and directrix of the parabola from the given equation. \"\r<BR>\n" );
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document.write( "The first problem is: y^2=16x \r<BR>\n" );
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document.write( "I tried using this formula: \"(y-k)^2=4p (x-h) and only figured out the vertex, which in this case would be (0,0). I don't understand the rest. I tried finding the directrix and focus but I just don't understand how to at all. Please help. Thank you! :) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #483617 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=483617\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Find the focus and directrix of the parabola from the given equation. \"<BR>\n" );
document.write( "The first problem is: y^2=16x <BR>\n" );
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document.write( "There are 4 different forms of equation for parabolas with vertices at the origin:<BR>\n" );
document.write( "x^2=4py (parabola opens up)<BR>\n" );
document.write( "x^2=-4py (parabola opens down)<BR>\n" );
document.write( "y^2=4px (parabola opens right)<BR>\n" );
document.write( "y^2=-4px (parabola opens left)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "Equation of given parabola y^2=16x is the 3rd form listed<BR>\n" );
document.write( "It is a parabola that opens right with vertex at (0,0)<BR>\n" );
document.write( "Its axis of symmetry:y=0 or x-axis<BR>\n" );
document.write( "4p=16<BR>\n" );
document.write( "p=4<BR>\n" );
document.write( "directrix:x=-4 (p-distance to the left of the vertex on the axis of symmetry<BR>\n" );
document.write( "focus:(4,0)(p-distance to the right of the vertex on the axis of symmetry </SPAN>\n" );
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