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  • Perplex
    IB Math AIHL
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    Sequences & Series
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    Problems

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    Problem Bank - Sequences & Series

    Access custom-built, exam-style problems for sequences & series. Each problem has a full solution and mark-scheme, as well as AI grading and support.

    Ask Plex AI about problem 43

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    IB: 7
    43

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    Let Sn​ be the sum of the first n terms of an arithmetic sequence with first term u1​ and common difference d, where u1​>d.


    S1​,S3​ and S8​ are consecutive terms in a geometric sequence with common ratio r.

    1. Find the value of r.

      [6]

    It is given that the first term of the arithmetic sequence is 3, and that the sum of the first k terms of the geometric series is greater than 104.

    1. Find the smallest possible value of k.

      [4]
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