document.write( "Question 255741: Write a rule and find the given term in the geometric sequence described below. Show your work. What is the eighth term when the first term is -4 and the common ratio is -1/2? \n" ); document.write( "

Algebra.Com's Answer #188005 by drk(1908) $\"\"$ $\"About$

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The formula for geometric sequences is
\n" ); document.write( "(i) $\"Tn+=+a%2Ar%5E%28n-1%29\"$
\n" ); document.write( "using given infpormation, we get
\n" ); document.write( "(ii) $\"-4+=+a%2A%28-1%2F2%29%5E%281-1%29\"$
\n" ); document.write( "this is
\n" ); document.write( "(iii) $\"-4+=+a%2A%28-1%2F2%29%5E%280%29\"$
\n" ); document.write( "or
\n" ); document.write( "(iv) $\"a+=+-4\"$
\n" ); document.write( "Now, (i) becomes
\n" ); document.write( "(v) $\"T%28n%29+=+-4%28-1%2F2%29%5E%28n-1%29\"$
\n" ); document.write( "the 8th term is
\n" ); document.write( "(vi) $\"T%288%29+=+-4%28-1%2F2%29%5E%288-1%29\"$
\n" ); document.write( "or
\n" ); document.write( "(vii) $\"T%288%29+=+-4%28-1%2F2%29%5E%287%29\"$
\n" ); document.write( " $\"T%288%29+=+4%2F128\"$
\n" ); document.write( "T(8) = 1/32 \n" ); document.write( "

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