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Find the sum of the first 8 terms of the...

Find the sum of the first 8 terms of the series 2,6,18,54.

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Here , a=2 and `r=6/2=3`
`S_n=a((r^n-1)/(r-1))=(2(3^n-1))/((3-1))= 3^n-1`. Then `S_8= 3^8-1=6560`
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MAHAVEER PUBLICATION-SERIES-QUESTION BANK
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  12. If 3^(rd) term of an arithmetic progression is and term is 18 and 17^(...

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