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Science & Mathematics by Anonymous 2018-05-18 21:09:07
Social Science
What formula would I use to find the sum of 3(-2)^n from n=2 to n=8?
3 answers
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Anonymous
an = 3(-2)^n a2 + a3 + a4 + a5 + a6 + a7 + a8 = 12 - 24 + 48 - 96 + 192 - 384 + 768 = 1020 - 504 = 516
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Anonymous
That's only seven terms. Just write the value of each term, and add them up. You don't need any more formula than that.
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Anonymous
3(-2)^n from n = 2 to n = 8 12 - 24 + 48 - 96 + 192 - 384 + 768 = 1020 - 504 = 516