document.write( "Question 1195639: Let S={1,2,3,4,5,6,7,8,9,10} be the universal set.\r
\n" ); document.write( "\n" ); document.write( "Let sets A, B, and C be subsets of S , where:\r
\n" ); document.write( "\n" ); document.write( "Set A={1,6,7,10}\r
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\n" ); document.write( "\n" ); document.write( "Set B={2,9,10}\r
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\n" ); document.write( "\n" ); document.write( "Set C={3,4,5,7,8}\r
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\n" ); document.write( "\n" ); document.write( "LIST the elements in the set A∩B∩C:A∩B∩C= {___}\r
\n" ); document.write( "\n" ); document.write( "LIST the elements in the set A∪B∪C:A∪B∪C= {__}
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Algebra.Com's Answer #828282 by math_tutor2020(3817)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "∩ is the intersection symbol
\n" ); document.write( "U is the union symbol\r
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\n" ); document.write( "\n" ); document.write( "Set A∩B is where we look at elements in both sets A and B at the same time. This is the overlapped region in the Venn Diagram.\r
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\n" ); document.write( "\n" ); document.write( "Similarly, A∩B∩C looks at numbers in all three sets at the same time. \r
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\n" ); document.write( "\n" ); document.write( "Set A={1,6,7,10}
\n" ); document.write( "Set B={2,9,10}
\n" ); document.write( "Set C={3,4,5,7,8}\r
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\n" ); document.write( "\n" ); document.write( "The value 1 is in set A, but not in any other set
\n" ); document.write( "6 is in set A, but not in any other set
\n" ); document.write( "7 is in A and C, but not set B, so this value is crossed off as well
\n" ); document.write( "10 is in A and B, but not in set C\r
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\n" ); document.write( "\n" ); document.write( "The values 1,6,7 and 10 are not found in all three sets.
\n" ); document.write( "As you can see, we only need to check one set to determine A∩B∩C since this intersected set must consist of values from that particular single set mentioned.\r
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\n" ); document.write( "\n" ); document.write( "In other words, there isn't any value that is in all three sets at the same time. \r
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\n" ); document.write( "\n" ); document.write( "Therefore, A∩B∩C = { } is the empty set.
\n" ); document.write( "We write two curly braces with nothing between them.
\n" ); document.write( "Not even 0 is in this set.
\n" ); document.write( "The set { } is different from { 0 }\r
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\n" ); document.write( "\n" ); document.write( "For the next part, we'll be doing set union.
\n" ); document.write( "A∪B means we combine sets A and B into one bigger set.
\n" ); document.write( "Toss out any duplicates.\r
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\n" ); document.write( "\n" ); document.write( "Example:
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document.write( "A = {1,2}\r\n" );
document.write( "B = {3,4}\r\n" );
document.write( "A∪B = {1,2     3,4}\r\n" );
document.write( "A∪B = {1,2,3,4}\r\n" );
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\n" ); document.write( "The spacing is intentional to show how sets A and B combine together. When writing the actual union, you'd just write a list of numbers like normal without the massive gap.\r
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\n" ); document.write( "\n" ); document.write( "Another example:
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document.write( "A = {1,2,3}\r\n" );
document.write( "B = {3,4,5}\r\n" );
document.write( "A∪B = {1,2,3     3,4,5}\r\n" );
document.write( "A∪B = {1,2,3     3,4,5}\r\n" );
document.write( "A∪B = {1,2,3,4,5}\r\n" );
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\n" ); document.write( "We combine the 1,2,3 with 3,4,5
\n" ); document.write( "Cross off the second copy of 3 to avoid duplicates.\r
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\n" ); document.write( "\n" ); document.write( "Going back to the original problem
\n" ); document.write( "Set A={1,6,7,10}
\n" ); document.write( "Set B={2,9,10}
\n" ); document.write( "Set C={3,4,5,7,8}\r
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\n" ); document.write( "\n" ); document.write( "We have
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document.write( "A∪B∪C = {1,6,7,10,        2,9,10,       3,4,5,7,8}\r\n" );
document.write( "A∪B∪C = {1,2,3,4,5,6,7,8,9,10}\r\n" );
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\n" ); document.write( "Common practice is to sort the values in the set from smallest to largest.
\n" ); document.write( "Don't forget to erase any duplicates.\r
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\n" ); document.write( "\n" ); document.write( "It turns out that we have the universal set S = {1,2,3,4,5,6,7,8,9,10} as the result of the union of all three sets mentioned.
\n" ); document.write( "All of the values in the universe are found in set A, set B, or set C.\r
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\n" ); document.write( "\n" ); document.write( "We have this interesting contrast going on.
\n" ); document.write( "A∩B∩C is the empty set, aka \"nothing\"
\n" ); document.write( "A∪B∪C consists of everything in the universal set.
\n" ); document.write( "This won't always happen. It is possible your teacher purposefully crafted these sets in this fashion to attain this dichotomy.\r
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\n" ); document.write( "\n" ); document.write( "Answers:
\n" ); document.write( "A∩B∩C = { } which is the empty set
\n" ); document.write( "A∪B∪C = {1,2,3,4,5,6,7,8,9,10} which in this case is the universal set
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