document.write( "Question 550929: Direction: use one of the formulas for special series to find the sum of the series.
\n" ); document.write( "42
\n" ); document.write( "∑ 1
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\n" ); document.write( "1. 42 is on top of the symbol, i=1 is on bottom and 1 on right side.
\n" ); document.write( "2. 5 on top, n on right, n=1 on bottom. the answer is 15 but how?
\n" ); document.write( "3. 18 on top, i=1 on bottom, i on right.
\n" ); document.write( "4. 20 on top, k on right, k=1 on bottom
\n" ); document.write( "5. 6 on top, n^2 on right, n=1 on bottom.
\n" ); document.write( "6. 10 on top, i^2 on right, i=1 on bottom
\n" ); document.write( "7. 12 on top, i^2 on right, i=1 on bottom
\n" ); document.write( "8. 35 on top, k^2 on right, k=1 on bottom
\n" ); document.write( "again all these problems are shown in this symbol: ∑
\n" ); document.write( "thanks for ur help and happy new year!\r
\n" ); document.write( "\n" ); document.write( "please show ur work with each of the problems so i could understand it. thank you very much.
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Algebra.Com's Answer #359255 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "I'll do 4 of them.  You can do the other 4.  They are similar to these.\r\n" );
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\n" ); document.write( "1. 42 is on top of the symbol, i=1 is on bottom and 1 on right side.
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document.write( "\"sum%281%2Ci=1%2C42%29\" = 1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1 = 42\r\n" );
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\n" ); document.write( "2. 5 on top, n on right, n=1 on bottom. the answer is 15 but how?
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document.write( "\"sum%28n%2C1=1%2C5%29\" = 1+2+3+4+5 = 15 We didn't need a formula but we can use it:\r\n" );
document.write( "              \"n%28n%2B1%29%2F2\" = \"5%285%2B1%29%2F2\" = \"%28%285%29%286%29%29%2F2\" = 15\r\n" );
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\n" ); document.write( "4. 20 on top, k on right, k=1 on bottom
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document.write( "\"sum%28k%2Ck=1%2C20%29\" = 1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20\r\n" );
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document.write( "We use the formula  \"n%28n%2B1%29%2F2\" = \"20%2820%2B1%29%2F2\" = \"%28%2820%29%2821%29%29%2F2\" = 210\r\n" );
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\n" ); document.write( "8. 35 on top, k^2 on right, k=1 on bottom
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document.write( "\"sum%28k%5E2%2Ci=1%2C35%29\" = 1²+2²+3²+4²+5²+6²+7²+8²+9²+10²+11²+12²+13²+14²+15²+16²+17²+18²+19²+20²+21²+22²+23²+24²+25²+26²+27²+28²+29²+30²+31²+32²+33²+34²+35²\r\n" );
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document.write( "We use the formula \"n%28n%2B1%29%282n%2B1%29%2F6\" = \"35%2835%2B1%29%282%2A35%2B1%29%2F6\" = \"%28%2835%29%2836%29%2870%2B1%29%29%2F6\" = \"%28%2835%29%2836%29%2871%29%29%2F6\" = 14910.\r\n" );
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document.write( "Edwin
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