document.write( "Question 302713: Please Help,
\n" ); document.write( "Estimate the area under the curve { { { f(x)= -x^2+4x+4.25 over 0 <= x <= 5 } } } . Use 5 intervals. \r
\n" ); document.write( "\n" ); document.write( "I tried to graph it on a graphing calculator first, but I think it was wrong because I can't enter 0 <= x <= 5. Here is the link of the graphed equation: http://my.hrw.com/math06_07/nsmedia/tools/Graph_Calculator/graphCalc.html \r
\n" ); document.write( "\n" ); document.write( "Thanks for the help :)
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Algebra.Com's Answer #217031 by Fombitz(32388)\"\" \"About 
You can put this solution on YOUR website!
You didn't specify a method.
\n" ); document.write( "Break up the area into 5 regions.
\n" ); document.write( "Calculate an average value of f(x) and the right and left endpoint.
\n" ); document.write( "Then multiply the average value of f(x) by dx in each region.
\n" ); document.write( "\"+x=0\", \"+f%280%29=4.25\"
\n" ); document.write( "\"+x=1\", \"+f%281%29=7.25\"
\n" ); document.write( "\"+x=2\", \"+f%282%29=8.25\"
\n" ); document.write( "\"+x=3\", \"+f%283%29=7.25\"
\n" ); document.write( "\"+x=4\", \"+f%284%29=4.25\"
\n" ); document.write( "\"+x=5\", \"+f%285%29=-0.75\"
\n" ); document.write( "SO then area 1 equals,
\n" ); document.write( "\"A1=%281%2F2%29%28f%280%29%2Bf%281%29%29%2A%281-0%29=5.75+\"
\n" ); document.write( "\"A2=%281%2F2%29%28f%281%29%2Bf%282%29%29%2A%282-1%29=7.75\"
\n" ); document.write( "\"A3=%281%2F2%29%28f%282%29%2Bf%283%29%29%2A%283-2%29=7.75\"
\n" ); document.write( "\"A4=%281%2F2%29%28f%283%29%2Bf%284%29%29%2A%284-3%29=5.75\"
\n" ); document.write( "\"A5=%281%2F2%29%28f%284%29%2Bf%285%29%29%2A%285-4%29=1.75\"
\n" ); document.write( "\"Atot=A1%2BA2%2BA3%2BA4%2BA5=28.75\"
\n" ); document.write( "The exact value is \"29.583\" so that's a pretty good approximation (within 3%).
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