Complex numbers

  • 8 Methods for Three By One
    problem
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    8 Methods for Three by One

    Age
    14 to 18
    Challenge level
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    This problem in geometry has been solved in no less than EIGHT ways by a pair of students. How would you solve it? How many of their solutions can you follow? How are they the same or different? Which do you like best?
  • Complex partial fractions
    problem
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    Complex Partial Fractions

    Age
    16 to 18
    Challenge level
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    To break down an algebraic fraction into partial fractions in which all the denominators are linear and all the numerators are constants you sometimes need complex numbers.
  • Three by One
    problem
    Favourite

    Three by One

    Age
    16 to 18
    Challenge level
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    There are many different methods to solve this geometrical problem - how many can you find?

  • Roots and Coefficients
    problem

    Roots and Coefficients

    Age
    16 to 18
    Challenge level
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    If xyz = 1 and x+y+z =1/x + 1/y + 1/z show that at least one of these numbers must be 1. Now for the complexity! When are the other numbers real and when are they complex?
  • Sextet
    problem

    Sextet

    Age
    16 to 18
    Challenge level
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    Investigate x to the power n plus 1 over x to the power n when x plus 1 over x equals 1.
  • Complex Rotations
    problem

    Complex Rotations

    Age
    16 to 18
    Challenge level
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    Choose some complex numbers and mark them by points on a graph. Multiply your numbers by i once, twice, three times, four times, ..., n times? What happens?
  • Footprints
    problem

    Footprints

    Age
    16 to 18
    Challenge level
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    Make a footprint pattern using only reflections.
  • Pumping the Power
    problem

    Pumping the Power

    Age
    16 to 18
    Challenge level
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    What is an AC voltage? How much power does an AC power source supply?
  • 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.
  • Complex Sine
    problem

    Complex Sine

    Age
    16 to 18
    Challenge level
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    Solve the equation sin z = 2 for complex z. You only need the formula you are given for sin z in terms of the exponential function, and to solve a quadratic equation and use the logarithmic function.