document.write( "Question 1044698: Find the sum of the terms of a geometric sequence where the first term is 4, the last term is 324, and the common ratio is 3.
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Algebra.Com's Answer #660042 by MathLover1(20850)\"\" \"About 
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\n" ); document.write( "To find the sum of a certain number of terms of a geometric sequence:\r
\n" ); document.write( "\n" ); document.write( "\"S%5Bn%5D=a%5B1%5D%281-r%5En%29%2F%281-r%29\"\r
\n" ); document.write( "\n" ); document.write( "where \"S%5Bn%5D\"is the sum of \"n\" terms (nth partial sum),
\n" ); document.write( " \"a%5B1%5D\" is the first term, \"r\" is the common ratio.\r
\n" ); document.write( "\n" ); document.write( "if given the first term is \"a%5B1%5D=4\", the last term is \"a%5Bn%5D=324\", and the common ratio is \"r=3\" than we need first to find what number is the last term:\r
\n" ); document.write( "\n" ); document.write( "To find any term of a geometric sequence:
\n" ); document.write( "\"a%5Bn%5D=a%5B1%5D%2Ar%5E%28n-1%29\"
\n" ); document.write( "where a[1] is the first term of the sequence, \"r+\"is the common ratio, \"n\" is the number of the term to find\r
\n" ); document.write( "\n" ); document.write( "\"324=4%2A3%5E%28n-1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"324%2F4=3%5E%28n-1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"81=3%5E%28n-1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"3%5E4=3%5E%28n-1%29\".........since base same, exponents must be same too, so we have\r
\n" ); document.write( "\n" ); document.write( "\"4=n-1\"\r
\n" ); document.write( "\n" ); document.write( "\"n=5\"-> so, your sequence have \"5\" terms\r
\n" ); document.write( "\n" ); document.write( "than the sum will be:\r
\n" ); document.write( "\n" ); document.write( "\"S%5B5%5D=4%281-3%5E5%29%2F%281-3%29\"\r
\n" ); document.write( "\n" ); document.write( "\"S%5B5%5D=4%281-243%29%2F%28-2%29\"\r
\n" ); document.write( "\n" ); document.write( "\"S%5B5%5D=2%28-242%29%2F%28-1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"S%5B5%5D=2%28242%29\"\r
\n" ); document.write( "\n" ); document.write( "\"S%5B5%5D=484\"\r
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