document.write( "Question 1193516: Find the number of terms in this geometric series\r
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Algebra.Com's Answer #825565 by ikleyn(52790)\"\" \"About 
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document.write( "Use the formula for the sum of a geometric progression\r\n" );
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document.write( "    \"S%5Bn%5D\" = \"a%2A%28%28r%5En-1%29%2F%28r-1%29%29\",\r\n" );
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document.write( "where \"a\" is the first term and \"r\" is the common ratio.\r\n" );
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document.write( "In your case a= -4, r= -4, so the formula is\r\n" );
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document.write( "    52428 = \"%28-4%29%2A%28%28%28-4%29%5En-1%29%2F%28-4-1%29%29\",\r\n" );
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document.write( "or\r\n" );
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document.write( "    52428 = \"%28-4%29%2A%28%28%28-4%29%5En-1%29%2F%28-5%29%29\".\r\n" );
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document.write( "From this formula,\r\n" );
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document.write( "    \"%28-4%29%5En+-+1\" = \"52428%2A%28%28-5%29%2F%28-4%29%29\" = 65535\r\n" );
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document.write( "    \"%28-4%29%5En\" = 65535 + 1 = 65536 = \"4%5E8\",\r\n" );
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document.write( "so\r\n" );
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document.write( "    n = 8.\r\n" );
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document.write( "ANSWER.  n = 8.\r\n" );
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\n" ); document.write( "\n" ); document.write( "On geometric progressions,  see introductory lessons\r
\n" ); document.write( "\n" ); document.write( "    - Geometric progressions\r
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\n" ); document.write( "\n" ); document.write( "    - Problems on geometric progressions\r
\n" ); document.write( "\n" ); document.write( "    - Word problems on geometric progressions\r
\n" ); document.write( "\n" ); document.write( "in this site.\r
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\n" ); document.write( "\n" ); document.write( "Also,  you have this free of charge online textbook in ALGEBRA-II in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this online textbook under the topic
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\n" ); document.write( "\n" ); document.write( "Save the link to this textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-II
\n" ); document.write( "https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "into your archive and use when it is needed.\r
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