document.write( "Question 1118070: Find the sum of the series 1+3.5+6+8.5+......+101
\n" ); document.write( "Find the sum of the first 23 term of the AP 4-3-10.....
\n" ); document.write( "An arithmetic series have 1st term as 4 and common difference as 1/2 find the first 20term
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\n" ); document.write( "Find the sum of arithmetic series term 1common difference 3 and last term 100
\n" ); document.write( "Find the sum of d first 20 term of arithmetic is identical to the sum of first 22 term. If the common difference is -2 find the first term
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Algebra.Com's Answer #733295 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
Find the sum of the series 1+3.5+6+8.5+......+101.
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document.write( "Sn = (n/2)(a1 + an)\r\n" );
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document.write( "a1 = 1\r\n" );
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document.write( "But we need first to determine n.\r\n" );
document.write( "To do that we need d:\r\n" );
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document.write( "d = 3.5-1 = 6-3.5 = 8.5-6 = 2.5\r\n" );
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document.write( "an = a1 + (n - 1)∙d\r\n" );
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document.write( "101 = a1 + (n - 1)∙2.5\r\n" );
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document.write( "Solve that and get n = 41\r\n" );
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document.write( "Sn = (n/2)(a1 + an)\r\n" );
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document.write( "S41 = (41/2)(1 + a41)\r\n" );
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document.write( "S41 = (41/2)(1 + 101)\r\n" );
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document.write( "S41 = (41/2)(102)\r\n" );
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document.write( "S41 = 2091\r\n" );
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\n" ); document.write( "Find the sum of the first 23 term of the AP 4-3-10.....
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document.write( "First find d:\r\n" );
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document.write( "d = -3 - 4 = -10 - (-3) = -7\r\n" );
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document.write( "Then use\r\n" );
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document.write( "Sn = (n/2)[2∙a1 + (n-1)∙d\r\n" );
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document.write( "with n = 23, a1 = 4, d = -7 \r\n" );
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\n" ); document.write( "An arithmetic series have 1st term as 4 and common difference as 1/2 find the first 20 terms.
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document.write( "Write the first term as 4 and keep adding 1/2 over and over until\r\n" );
document.write( "you have written 20 terms. To get you started,\r\n" );
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document.write( "the 2nd term is 4 + 1/2 = 8/2 + 1/2 = 9/2,\r\n" );
document.write( "the 3rd term is 9/2 + 1/2 = 10/2 = 5,\r\n" );
document.write( "etc., etc.,\r\n" );
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document.write( "Edwin
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