sum of sequence a level | Revision Server | Page 1

vestal monolith Mar 22, 2023, 8:11 PM

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Keep getting different answer to my calc and dont understand why

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Mine =8673
Calc=8847

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Im using n/2[first term+last term]

willow kraken Mar 22, 2023, 10:39 PM

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What did u write above the sigma I can’t read it

distant locust Mar 22, 2023, 10:40 PM

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not sure why ur getting it wrong if ur using that formula and that number at the top is 59

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59/2 (295+5) =8850

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and then you subtract 3 because sum of 3(-1)^n just depends what the last number value of n is as it cancels itself out and 59 is odd so its -1

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so 8850-3 =8847 which is what ur calc got

#sum of sequence a level