document.write( "Question 1062804: find the nth term of this sequence: \r
\n" ); document.write( "\n" ); document.write( "-1/3,1/9,-1/27,1/81,..... \n" ); document.write( "
Algebra.Com's Answer #677794 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Looking at the denominators (3, 9, 27, 81, ...) they are powers of 3\r
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\n" ); document.write( "\n" ); document.write( "3^1 = 3
\n" ); document.write( "3^2 = 9
\n" ); document.write( "3^3 = 27
\n" ); document.write( "3^4 = 81
\n" ); document.write( "and so on...\r
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\n" ); document.write( "\n" ); document.write( "The terms are almost of the form 1/(3^n) where n is a positive whole number starting at n = 1. However, notice that the terms alternate in sign. This means we need to have (-1)^n in there to have the terms alternate\r
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\n" ); document.write( "\n" ); document.write( "If n = 1, then (-1)^n = (-1)^1 = -1 making the first term negative like we want
\n" ); document.write( "If n = 2, then (-1)^n = (-1)^2 = 1 making the second term positive like we want
\n" ); document.write( "and so on...\r
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\n" ); document.write( "\n" ); document.write( "Put this all together and the nth term is \"%28-1%29%5En%2A%281%2F%283%5En%29%29\" \n" ); document.write( "
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