Powers and roots

  • How Many Solutions?
    problem
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    How Many Solutions?

    Age
    16 to 18
    Challenge level
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    Find all the solutions to the this equation.

  • Giants
    problem
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    Giants

    Age
    16 to 18
    Challenge level
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    Which is the bigger, 9^10 or 10^9 ? Which is the bigger, 99^100 or 100^99 ?

  • In Between
    problem
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    In Between

    Age
    16 to 18
    Challenge level
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    Can you find the solution to this algebraic inequality?
  • Absurdity Again
    problem

    Absurdity Again

    Age
    16 to 18
    Challenge level
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    What is the value of the integers a and b where sqrt(8-4sqrt3) = sqrt a - sqrt b?
  • Route to Root
    problem

    Route to Root

    Age
    16 to 18
    Challenge level
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    A sequence of numbers x1, x2, x3, ... starts with x1 = 2, and, if you know any term xn, you can find the next term xn+1 using the formula: xn+1 = (xn + 3/xn)/2 . Calculate the first six terms of this sequence. What do you notice? Calculate a few more terms and find the squares of the terms. Can you prove that the special property you notice about this sequence will apply to all the later terms of the sequence? Write down a formula to give an approximation to the cube root of a number and test it for the cube root of 3 and the cube root of 8. How many terms of the sequence do you have to take before you get the cube root of 8 correct to as many decimal places as your calculator will give? What happens when you try this method for fourth roots or fifth roots etc.?
  • Mod 7
    problem

    Mod 7

    Age
    16 to 18
    Challenge level
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    Find the remainder when 3^{2001} is divided by 7.
  • Like Powers
    problem

    Like Powers

    Age
    11 to 14
    Challenge level
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    Investigate $1^n + 19^n + 20^n + 51^n + 57^n + 80^n + 82^n $ and $2^n + 12^n + 31^n + 40^n + 69^n + 71^n + 85^n$ for different values of n.
  • Two Many
    problem

    Two Many

    Age
    11 to 14
    Challenge level
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    What is the least square number which commences with six two's?
  • Lost in Space
    problem

    Lost in Space

    Age
    14 to 16
    Challenge level
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    How many ways are there to count 1 - 2 - 3 in the array of triangular numbers? What happens with larger arrays? Can you predict for any size array?
  • Consecutive Squares
    problem

    Consecutive Squares

    Age
    14 to 16
    Challenge level
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    The squares of any 8 consecutive numbers can be arranged into two sets of four numbers with the same sum. True of false?