document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=484458>Question 484458</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A cuboid of volume 1125cm^3 has length equal to three times the breadth.\r<BR>\n" );
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document.write( "(A)- show that the surface area of the cuboid may be expressed as 6x^2+3000/x\r<BR>\n" );
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document.write( "(B) - find the dimensions of the cuboid that give the minimum surface area. \r<BR>\n" );
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document.write( "I think i have a right, just need to check but i am completely stuck on b, help would be much appreciated.\r<BR>\n" );
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document.write( "the breadth is x and the length is 3x. <BR>\n" );
document.write( "thanks </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #331497 by </B><A HREF=/tutors/aboutme.mpl?userid=chessace><B>chessace(471)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=chessace><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=chessace><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=331497\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Yes, you are on the right track.<BR>\n" );
document.write( "You have surface area as f(x), so to find the min,<BR>\n" );
document.write( "differentiate and set to 0.<BR>\n" );
document.write( "12x-3000x^-2 = 0<BR>\n" );
document.write( "*(1/12)x^2: x^3 - 250 = 0<BR>\n" );
document.write( "breath x = 5 cubeRoot(2) cm<BR>\n" );
document.write( "L = 15 cubeRoot(2) cm<BR>\n" );
document.write( "H = 15/cubeRoot(4) cm<BR>\n" );
document.write( "Double check and the product is indeed 1125 cm^3\r<BR>\n" );
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document.write( " </SPAN>\n" );
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