document.write( "Question 1022028: Find the sum of the first 10 terms of geometric series starting at 10 and decreasing by a factor of 2 each time?
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document.write( "A 5 - 5/2^8
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document.write( "B 10 - 5/2^8
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document.write( "C 15 - 5/2^8
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document.write( "D 20 - 5/2^8 \n" );
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Algebra.Com's Answer #637709 by rothauserc(4718)![]() ![]() You can put this solution on YOUR website! the sum of a geometric series is Sn = a(1 - r^n) / (1 - r) where a is the first term, r is the common ratio, and n is n consecutive terms \n" ); document.write( ": \n" ); document.write( "S10 = 10(1 - (1/2)^10) / ( 1 - (1/2)) \n" ); document.write( ": \n" ); document.write( "S10 = 10(1 - (1/(2^10))) / (1/2) \n" ); document.write( ": \n" ); document.write( "divide by 1/2 means multiply by 2 \n" ); document.write( "S10 = 20(1 - (1 /2^10) \n" ); document.write( ": \n" ); document.write( "20 = 2^2 * 5 \n" ); document.write( "S10 = 20 - (((2^2)*5)/ 2^10) \n" ); document.write( ": \n" ); document.write( "S10 = 20 - (5 / 2^8) \n" ); document.write( ": \n" ); document.write( "*************************** \n" ); document.write( "Answer is D \n" ); document.write( "*************************** \n" ); document.write( " |