document.write( "Question 1207300: A company that manufactures dog food wishes to pack in closed cylindrical tins.
\n" ); document.write( "What should be the dimensions of each tin if it is to have a volume of 128πcm³
\n" ); document.write( "and the minimum possible surface area?
\n" ); document.write( "

Algebra.Com's Answer #845093 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"V=pi%2Ar%5E2%2Ah\"\r
\n" ); document.write( "\n" ); document.write( " surface area:\r
\n" ); document.write( "\n" ); document.write( "\"A=2pi%2Ar%2Ah%2B2pi%2Ar%5E2\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "given\r
\n" ); document.write( "\n" ); document.write( "\"V=128pi%2Acm%5E3\"\r
\n" ); document.write( "\n" ); document.write( "then\r
\n" ); document.write( "\n" ); document.write( "\"pi%2Ar%5E2%2Ah=128pi\"...simplify\r
\n" ); document.write( "\n" ); document.write( "\"r%5E2%2Ah=128\"\r
\n" ); document.write( "\n" ); document.write( "\"h=128%2Fr%5E2\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "substitute in formula for area\r
\n" ); document.write( "\n" ); document.write( "\"A=2pi%2Ar%28128%2Fr%5E2%29%2B2pi%2Ar%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"A=2pi%2A%28128%2Fr%29%2B2pi%2Ar%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"A=2pi%2A%28128%2Fr%29%2B2pi%2Ar%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"A=2pi%2Ar%5E2+%2B+%28256pi%29%2Fr\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "to minimize, derivate\r
\n" ); document.write( "\n" ); document.write( "first derivative\r
\n" ); document.write( "\n" ); document.write( "\"A\"\"%28r%29=%284pi%2Ar%5E3+-+256pi%29%2Fr%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"A\"\"%28r%29=4pi%2Ar-256pi\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "second derivative\r
\n" ); document.write( "\n" ); document.write( "\"A\"′'\"%28r%29=4pi\"\r
\n" ); document.write( "\n" ); document.write( "now, \"A\"′′\"%284%29%3E0\" at \"r+=+4\" is point of minima\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "substitute \"r=4+\"in \"h=128%2Fr%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"h=128%2F%284%29%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"h=128%2F16\"\r
\n" ); document.write( "\n" ); document.write( "\"h=8\"\r
\n" ); document.write( "\n" ); document.write( "so, minimum surface area the can should have a radius of \"4cm+\"and height of \"8cm\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );