Reasoning, convincing and proving

  • Staircase
    problem

    Staircase

    Age
    16 to 18
    Challenge level
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    Solving the equation x^3 = 3 is easy but what about solving equations with a 'staircase' of powers?
  • Tetra Inequalities
    problem

    Tetra inequalities

    Age
    16 to 18
    Challenge level
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    Can you prove that in every tetrahedron there is a vertex where the three edges meeting at that vertex have lengths which could be the sides of a triangle?
  • Diverging
    problem

    Diverging

    Age
    16 to 18
    Challenge level
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    Show that for natural numbers x and y if x/y > 1 then x/y>(x+1)/(y+1}>1. Hence prove that the product for i=1 to n of [(2i)/(2i-1)] tends to infinity as n tends to infinity.
  • Latin Numbers
    problem

    Latin numbers

    Age
    14 to 16
    Challenge level
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    Can you create a Latin Square from multiples of a six digit number?
  • Pair Squares
    problem

    Pair squares

    Age
    16 to 18
    Challenge level
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    The sum of any two of the numbers 2, 34 and 47 is a perfect square. Choose three square numbers and find sets of three integers with this property. Generalise to four integers.
  • Basic Rhythms
    problem

    Basic rhythms

    Age
    16 to 18
    Challenge level
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    Explore a number pattern which has the same symmetries in different bases.
  • Target Six
    problem

    Target six

    Age
    16 to 18
    Challenge level
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    Show that x = 1 is a solution of the equation x^(3/2) - 8x^(-3/2) = 7 and find all other solutions.
  • 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)?
  • Prime AP
    problem

    Prime AP

    Age
    16 to 18
    Challenge level
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    What can you say about the common difference of an AP where every term is prime?

  • Sixational
    problem

    Sixational

    Age
    14 to 18
    Challenge level
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    The nth term of a sequence is given by the formula n^3 + 11n. Find the first four terms of the sequence given by this formula and the first term of the sequence which is bigger than one million. Prove that all terms of the sequence are divisible by 6.