my quadratic issue

Discussion in 'Homework Help' started by stupid, Nov 16, 2009.

  1. stupid

    Thread Starter Active Member

    Oct 18, 2009
    81
    0
    hi,
    how to simply s^{2}+(R/L)s + (1/LC)=0?

    my work,
    by quadratic
    [​IMG]-(R/L)±√((R/L)^{2}-(4/LC)) /2 =0

    -(R/2L)±√((R/L)^{2}-(4/LC)) /2 =0

    -(R/2L)±(1/2)√((R/L)^{2}-(4/LC))=0

    -(R/2L)±√((R/4L)^{2}-(1/LC)=0

    but the answer provided is -(R/2L)±[(R/2L)^{2}-(1/LC)]^{(1/2)}

    my problem is with (R/4L)^{2}

    thanks
     
  2. Ratch

    New Member

    Mar 20, 2007
    1,068
    3
    Hey Stupid,

    Why do you want to keep the three elements that make up the coefficients of the quadratic equation separate? That makes for a lot of complex algebra, and does not simplify anything. Combine the elements first to make each coefficient, and then apply the quadratic formula.

    Ratch
     
  3. steveb

    Senior Member

    Jul 3, 2008
    2,433
    469
    Yes, that is your problem. Double check your work and you'll see that you just simplified incorrectly. - simple algebra mistake. :)
     
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