document.write( "Question 907313: A rectangular storage container with an open top is to have a volume of 10 m3. The length of this base is twice the width. Material for the base costs $20 per square meter. Material for the sides costs $12 per square meter. Find the cost of materials for the cheapest such container. (Round your answer to the nearest cent.)\r
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Algebra.Com's Answer #550238 by josgarithmetic(39617)\"\" \"About 
You can put this solution on YOUR website!
x for length, y for width,
\n" ); document.write( "x=2y
\n" ); document.write( "volume is 10 cubic meters, so if for z height,
\n" ); document.write( "xyz=10\r
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\n" ); document.write( "\n" ); document.write( "Finding z:
\n" ); document.write( "\"%282y%29yz=10\"
\n" ); document.write( "\"2y%5E2%2Az=10\"
\n" ); document.write( "Still more information is needed to have a better relationship among the three dimensions.\r
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\n" ); document.write( "\n" ); document.write( "These are the costs of the different rectangular parts altogether:
\n" ); document.write( "\"xy%2A20%2B2%2Axz%2A12%2B2%2Ayz%2A12\"
\n" ); document.write( "\"20xy%2B24xz%2B24yz\"
\n" ); document.write( "and if you substitute for y,
\n" ); document.write( "\"20%282y%29y%2B24%282y%29%2B24yz\"
\n" ); document.write( "\"40y%5E2%2B48y%2B24yz\"-----This cost written in terms of y and z.\r
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\n" ); document.write( "\n" ); document.write( "You can use the earlier found, \"2y%5E2%2Az=10\" to either substitute for y or for z in the cost function.
\n" ); document.write( "First, simplify the \"10\" equation to \"z%2Ay%5E2=5\".
\n" ); document.write( "\"z=5%2Fy%5E2\"; substitute for z, done here.\r
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\n" ); document.write( "\n" ); document.write( "cost, \"40y%5E2%2B48y%2B24y%285%2Fy%5E2%29\"
\n" ); document.write( "\"highlight_green%28c%28y%29=40y%5E2%2B48y%2B120%2Fy%29\".\r
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\n" ); document.write( "\n" ); document.write( "This is probably meant as a calculus problem using the derivative \"dc%2Fdy\".
\n" ); document.write( "Form the derivative, and solve for y in \"dc%2Fdy=0\" to find and check extremes (for a minimum value for c).
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