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    I'm stuck on this series question.. and have no idea how this answer was reached. Please help... thanks so much!!

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    (Original post by Ipsooo)
    Name:  Screen Shot 2016-09-12 at 18.40.12.png
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    I'm stuck on this series question.. and have no idea how this answer was reached. Please help... thanks so much!!

    Attachment 579708579710
    This is a geometric series, first term x and common ratio 2x. Can you see why?

    Now use the formula for the geometric series \frac{a(1 - r^n)}{1-r} for the sum of the first n with a = x (first term), r = 2x (common ratio), n = 10 (first ten terms)
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    (Original post by Zacken)
    This is a geometric series, first term x and common ratio 2x. Can you see why?

    Now use the formula for the geometric series \frac{a(1 - r^n)}{1-r} for the sum of the first n with a = x (first term), r = 2x (common ratio), n = 10 (first ten terms)
    Oh dear, I've massively over complicated things... Thanks sooo much!!
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    (Original post by Ipsooo)
    Oh dear, I've massively over complicated things... Thanks sooo much!!
    No worries.


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