Sequence and series question; | Mathematics | Page 1

upbeat frigate Nov 18, 2022, 3:59 PM

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well, S here is basically just sum of 9 terms of geometric series (x + x^2 + ... part)

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and the series is geometric series x, x^2, x^3 + ... and arithmetic series ka, ka + 2a, ka + 4a

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you can see that the S can be rewritten as

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$\frac{x^{10}-x}{x-1} + 45a$

terse wrenBOT Nov 18, 2022, 4:01 PM

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John Math

upbeat frigate Nov 18, 2022, 4:01 PM

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which means that the sum of 9 terms of ka, (k+2)a, (k+4)a, ... is 45a

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you can solve it yourself now

outer marlin Nov 18, 2022, 4:02 PM

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okay

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thanks

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but its going till infinity?

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@upbeat frigate

upbeat frigate Nov 18, 2022, 4:05 PM

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no

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well, the series are

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but we only care about first 9 terms

outer marlin Nov 18, 2022, 4:06 PM

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bruuh my bad

#Sequence and series question;