document.write( "Question 1058007: A rectangular storage container with an open top is to have a volume of 12 cubic meters. The length of its base is twice the width. Material for the base costs 13 dollars per square meter. Material for the sides costs 7 dollars per square meter. Find the cost of materials for the cheapest such container. \n" ); document.write( "
Algebra.Com's Answer #673067 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
Let \"+h+\" = the height of the box
\n" ); document.write( "Let \"+w+\" = the width
\n" ); document.write( "\"+2w+\" = the length
\n" ); document.write( "------------------------
\n" ); document.write( "The cost of the base is:
\n" ); document.write( "\"+2w%2Aw%2A13+\"
\n" ); document.write( "\"+26w%5E2+\"
\n" ); document.write( "----------------
\n" ); document.write( "The area of the sides is:
\n" ); document.write( "\"+2%2Aw%2Ah+%2B+2%2A%28+2w+%29%2Ah+\"
\n" ); document.write( "\"+2w%2Ah+%2B+4w%2Ah+=+6w%2Ah+\"
\n" ); document.write( "The cost of the materials for sides is:
\n" ); document.write( "\"+6w%2Ah%2A7+=+42w%2Ah+\"
\n" ); document.write( "-----------------------------------
\n" ); document.write( "Also given:
\n" ); document.write( "\"+w%2A2w%2Ah+=+12+\"
\n" ); document.write( "\"+2w%5E2h+=+12+\"
\n" ); document.write( "\"+h+=+12%2F%28+2w%5E2+%29+\"
\n" ); document.write( "-----------------------
\n" ); document.write( "Let \"+C+\" = cost of materials
\n" ); document.write( "The cost for materials is:
\n" ); document.write( "\"+26w%5E2+%2B+42w%2Ah+\"
\n" ); document.write( "\"+26w%5E2+%2B+42w%2A%28+12%2F%28+2w%5E2+%29+%29+\"
\n" ); document.write( "\"+C+=+26w%5E2+%2B+252%2Fw+\"
\n" ); document.write( "---------------------------------
\n" ); document.write( "I don't know if this is for a calculus course, but
\n" ); document.write( "that's the only way I can solve it.
\n" ); document.write( "Take the derivative and set = zero
\n" ); document.write( "\"+52w+-+252%2Fw%5E2+=+0+\"
\n" ); document.write( "\"+52w+=+252%2Fw%5E2+\"
\n" ); document.write( "\"+52w%5E3+=+252+\"
\n" ); document.write( "\"+w%5E3+=+4.8462+\"
\n" ); document.write( "\"+w+=+1.6923+\"
\n" ); document.write( "and
\n" ); document.write( "\"+C%5B+min+%5D+=+26w%5E2+%2B+252%2Fw+\"
\n" ); document.write( "\"+C%5B+min+%5D+=+26%2A1.6923%5E2+%2B+252%2F1.6923+\"
\n" ); document.write( "\"+C%5B+min+%5D+=+74.4573+%2B+148.9098+\"
\n" ); document.write( "\"+C%5Bmin%5D+=+223.367+\"
\n" ); document.write( "The minimum cost is $223.37
\n" ); document.write( "------------------------------
\n" ); document.write( "Check:
\n" ); document.write( "Is the 2nd derivative positive? ( that makes it a min )
\n" ); document.write( "\"+52+-+252%2A%28-2%29%2Fw%5E3+\"
\n" ); document.write( "\"+52+%2B+504%2Fw%5E3+\" yes, it's positive
\n" ); document.write( "------------------------------------
\n" ); document.write( "Here's the plot of \"+C%28w%29+\":
\n" ); document.write( "\"+graph%28+400%2C+400%2C+-2%2C+10%2C+-400%2C+400%2C+26x%5E2+%2B+252%2Fx+%29+\"
\n" ); document.write( "I may have the right answer. Get another opinion on this\r
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