Mathematical induction

  • Obviously?
    problem

    Obviously?

    Age
    14 to 18
    Challenge level
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    Find the values of n for which 1^n + 8^n - 3^n - 6^n is divisible by 6.

  • Dirisibly Yours
    problem

    Dirisibly Yours

    Age
    16 to 18
    Challenge level
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    Find and explain a short and neat proof that 5^(2n+1) + 11^(2n+1) + 17^(2n+1) is divisible by 33 for every non negative integer n.

  • Farey Fibonacci
    problem

    Farey Fibonacci

    Age
    16 to 18
    Challenge level
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    Investigate Farey sequences of ratios of Fibonacci numbers.

  • OK! Now prove it
    problem

    Ok! Now Prove It

    Age
    16 to 18
    Challenge level
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    Make a conjecture about the sum of the squares of the odd positive integers. Can you prove it?

  • Binary Squares
    problem

    Binary Squares

    Age
    16 to 18
    Challenge level
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    If a number N is expressed in binary by using only 'ones,' what can you say about its square (in binary)?

  • Fibonacci Fashion
    problem

    Fibonacci Fashion

    Age
    16 to 18
    Challenge level
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    What have Fibonacci numbers to do with solutions of the quadratic equation x^2 - x - 1 = 0 ?

  • Farey Neighbours
    problem

    Farey Neighbours

    Age
    16 to 18
    Challenge level
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    Farey sequences are lists of fractions in ascending order of magnitude. Can you prove that in every Farey sequence there is a special relationship between Farey neighbours?

  • Particularly general
    problem

    Particularly General

    Age
    16 to 18
    Challenge level
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    By proving these particular identities, prove the existence of general cases.

  • Water Pistols
    problem

    Water Pistols

    Age
    16 to 18
    Challenge level
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    With n people anywhere in a field each shoots a water pistol at the nearest person. In general who gets wet? What difference does it make if n is odd or even?