document.write( "Question 364992: I have worked this problem before and got it wrong and so I'm trying to fix it to get second chance credit but I just dont understand it. Can someone please help?\r
\n" ); document.write( "\n" ); document.write( "Let X[cm] be the diameter of bolts in a production. Assume that X has the density f(x)=k(x-0.9)(1.1-x) if 0.9< x <1.1 and 0 otherwise. Determine k. graph f(x), and the mean and variance. \r
\n" ); document.write( "\n" ); document.write( "I dont know if there is any way to put graphs on here but if not can you please try and help as much as possible. I would so appreciate it.
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Algebra.Com's Answer #260232 by Fombitz(32388)\"\" \"About 
You can put this solution on YOUR website!
The integral of the density function from \"x=0.9\" to \"x=1.1\" must equal \"1\".
\n" ); document.write( "\"int%28k%28x-0.9%29%281.1-x%29%2Cdx%2C0.9%2C1.1%29=1\"\r
\n" ); document.write( "\n" ); document.write( "\"k%2Aint%28%28-x%5E2%2B2x-%2899%2F100%29%29%2Cdx%2C0.9%2C1.1%29=1\"
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\n" ); document.write( "\"-602%2F3000%2B1200%2F3000-594%2F3000=1%2Fk\"
\n" ); document.write( "\"1%2Fk=4%2F3000\"
\n" ); document.write( "\"highlight%28k=750%29\"
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\n" ); document.write( "\"graph%28300%2C300%2C0.9%2C1.1%2C-1%2C8%2C750%28x-0.9%29%281.1-x%29%29\"
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\n" ); document.write( "The left endpoint is \"x=0.9\", the right endpoint is \"x=1.1\".
\n" ); document.write( "The peak of \"7.5\" occurs when \"x=1\".
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\n" ); document.write( "Now that you have \"k\" you can solve for the mean and the variance.
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\n" ); document.write( "\"highlight%28mu=1%29\"
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\n" ); document.write( "\"V%2Fk=8%2F3000000\"
\n" ); document.write( "\"highlight%28V=1%2F500%29\"
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