document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1112654>Question 1112654</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find the equation of parabola with vertex at (4, 2), latus rectum 20, and opens downward. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #727705 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=727705\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "The form of the equation of a parabola that opens up or down that I like to use is this:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y-k+=+%281%2F%284p%29%29%28x-h%29%5E2 ALIGN=MIDDLE  ALT=\"y-k+=+%281%2F%284p%29%29%28x-h%29%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "In this form, the vertex, is (h,k), and p is the distance from the vertex to the focus and from the vertex to the directrix.  With that definition for p, 4p is the length of the latus rectum.<br><BR>\n" );
document.write( "In your problem the vertex and the length of the latus rectum are given, so you just need to plug in the values -- remembering that the coefficient 1/4p is negative because the parabola opens downward.<br><BR>\n" );
document.write( "Answer: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y-2+=+%28-1%2F20%29%28x-4%29%5E2 ALIGN=MIDDLE  ALT=\"y-2+=+%28-1%2F20%29%28x-4%29%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );