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    • Thread Starter


    A sequence of numbers U1, U2...Un is given by the formula Un = 3(2/3)^n - 1

    Find the values of u1 u2 and u3

    Which I did.

    When i cam to the second part I thought that to find the common ratio I do it by the usual method of dividing u1/u2 which is wrong obviously...

    I just found it a bit tricky to do because that seems like the thing you would do - does anyone understand what I mean?

    The common ratio is 2/3 - I suppose I am just frustrated that that just didnt come to mind as I was reading it and trying to do part b which asks

    show that the sum of the first u1 - u15 = -9.014

    Anyway explain it better to me than the book is??

    • Community Assistant

    Community Assistant
    It's U2/U1


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