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  • Perplex
    IB Math AASL
    /
    Sequences & Series
    /

    Problem Bank

    [Maximum mark: 18]

    Consider the sequence ​log2​x,log2​xa,log16​x…, where ​a>0​ and ​x>0,x=1.

    1. First consider the case where the series is geometric.

      1. Show that ​a=21​.

        [4]
      2. Given that ​S∞​=−6, find the value of ​x.

        [3]
    2. Next consider the case where the sequence is arithmetic.

      1. Show that ​a=85​​

        [3]
      2. Find ​d​ in the form ​d=qp​log2​x, where ​p,q∈Z.

        [1]
      3. Given that the sum of the first ​n​ terms in the sequence is ​Sn​=log2​(√x51​), find the value of ​n.

        [7]

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