document.write( "Question 1197285: Find the sum to Infinity of the following Sequence : 18, 12, 8, . . . \n" ); document.write( "
Algebra.Com's Answer #830505 by math_tutor2020(3817)\"\" \"About 
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\n" ); document.write( "a = 18 = first term\r
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\n" ); document.write( "\n" ); document.write( "Assuming this sequence is geometric, then,
\n" ); document.write( "r = common ratio
\n" ); document.write( "r = (term2)/(term1)
\n" ); document.write( "r = 12/18
\n" ); document.write( "r = 2/3\r
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\n" ); document.write( "\n" ); document.write( "Or
\n" ); document.write( "r = (term3)/(term2)
\n" ); document.write( "r = 8/12
\n" ); document.write( "r = 2/3\r
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\n" ); document.write( "\n" ); document.write( "2/3 = 0.667 approximately\r
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\n" ); document.write( "\n" ); document.write( "Since -1 < r < 1 is true, this means the infinitely many terms of this sequence add to some fixed value S
\n" ); document.write( "S = a/(1-r)
\n" ); document.write( "S = 18/(1-2/3)
\n" ); document.write( "S = 18/(3/3-2/3)
\n" ); document.write( "S = 18/(1/3)
\n" ); document.write( "S = 18*3/1
\n" ); document.write( "S = 54\r
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\n" ); document.write( "\n" ); document.write( "Answer: 54
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