word problem for "complex roots"

Discussion in 'Secondary Education' started by edu, Nov 1, 2012.

  1. edu

    edu Rookie

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    Nov 1, 2012

    Dear pals,
    Can anyone help give a real world problem that yeilds an equation (or of type) x^2+1=0 (should give complex roots )
    thanks.
     
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  3. Mathemagician

    Mathemagician Groupie

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    Nov 1, 2012

    Try p 32 or 59 here:

    http://glencoe.mcgraw-hill.com/sites/dl/free/007873830x/518871/a2wpp.pdf

    They are all highly contrived. In most cases the imaginary solutions would be extraneous unless the kids were working with currents (which I doubt). I wouldn't use word problems with complex roots. I would just say they may see it later in physics or higher maths. They can do plenty of word problems with quadratics and real roots...just my 2 cents...not everything needs to have an instant real-world application.
    I always tell my alg kids that sometimes they need to appreciate an idea even if it isn't immediately applicable. They seem ok with that level of honesty.
     
  4. Aliceacc

    Aliceacc Multitudinous

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    Nov 2, 2012

    Imaginary numbers simply don't come up a whole lot in the real world, so they're all going to be fairly contrived.

    That's OK; the older kids taking Algebra II should be able to get past the idea of "When does my mother ever use this?"
     
  5. edu

    edu Rookie

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    Nov 2, 2012

    Thank you. I taught complex numbers in Alg-2 class today. I slightly introduced the concept of electromagnetic field strength which is a complex sum of electric field strength and magnetic field strength

    electromagnetic field strength = electric field strength+i*magnetic field strength.


    Students are convinced. But I would have been more happy if I could give them a real example.

    --Cheers.


     
  6. Expo Markers

    Expo Markers Rookie

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    Nov 3, 2012

    Electrical engineers use imaginary numbers to find current and physicists use them for quantum mechanics.

    But the former requires Calculus. Sorry!
     

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