document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=889070>Question 889070</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Farmer Fred wants to fence in a rectangular pasture that is bordered on one side by a river. He plans to use 7200 feet of fence to enclose the other three sides . What should the dimensions of the pasture be if the enclosed area is to be maximum? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #537926 by </B><A HREF=/tutors/aboutme.mpl?userid=Fombitz><B>Fombitz(32388)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Fombitz><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=Fombitz><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=537926\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let the side parallel to the river be X and the other side Y.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=X%2BX%2BY=7200 ALIGN=MIDDLE  ALT=\"X%2BX%2BY=7200\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2X%2BY=7200 ALIGN=MIDDLE  ALT=\"2X%2BY=7200\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The area would then be,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A=XY ALIGN=MIDDLE  ALT=\"A=XY\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Substitute for Y using the perimeter equation,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Y=7200-2X ALIGN=MIDDLE  ALT=\"Y=7200-2X\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A=X%287200-2X%29=7200X-2X%5E2 ALIGN=MIDDLE  ALT=\"A=X%287200-2X%29=7200X-2X%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "To find the extrema, differentiate with respect to X and set the derivative equal to zero.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=dA%2FdX=7200-4X=0 ALIGN=MIDDLE  ALT=\"dA%2FdX=7200-4X=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=X=7200%2F4 ALIGN=MIDDLE  ALT=\"X=7200%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28X=1800%29 ALIGN=MIDDLE  ALT=\"highlight%28X=1800%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Then,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Y=7200-3600 ALIGN=MIDDLE  ALT=\"Y=7200-3600\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28Y=3600%29 ALIGN=MIDDLE  ALT=\"highlight%28Y=3600%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );