document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=877244>Question 877244</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Derive the equation of the parabola with a focus at (&#8722;5, 5) and a directrix of y = -1 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #529250 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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/cgi-bin/show-face.mpl?user=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=529250\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Derive the equation of the parabola with a focus at (&#8722;5, 5) and a directrix of y = -1<BR>\n" );
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document.write( "vertex is mid-way between the focus and directrix:<BR>\n" );
document.write( "vertex: (-5,2)<BR>\n" );
document.write( "standard form of a vertical parabola <BR>\n" );
document.write( "(x – h)^2 = 4p(y – k)<BR>\n" );
document.write( "(x – (-5))^2 = 4p(y – 2)<BR>\n" );
document.write( "(x + 5)^2 = 4p(y – 2)<BR>\n" );
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document.write( "p is the distance between the vertex and either the focus or directrix:<BR>\n" );
document.write( "p = 3<BR>\n" );
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document.write( "so our final equation is:<BR>\n" );
document.write( "(x + 5)^2 = 4*3(y – 2)<BR>\n" );
document.write( "(x + 5)^2 = 12(y – 2)\r<BR>\n" );
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document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );