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Question about cube root

  1. Jan 18, 2014 #1
    Lets say I was trying to figure out the restrictions of a radical equation and the function inside the radical was a cubic function. I know you have to make the equation inside greater than or equal to 0.
    In the case of a quadratic equation, you have to square root it once you bring everything to one side of the equality, giving you a positive and negative answer, is this the same for cube rooting it when figuring out the restrictions? You will have a positive and negative cube root?
  2. jcsd
  3. Jan 18, 2014 #2


    Staff: Mentor

  4. Jan 18, 2014 #3


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    No. [itex](-x)^3= -x^3[/itex] so there are not "positive and negative cube roots" of the same number. There will be one real cube root of a real number (other than 0) and two complex conjugate (non-real) roots.
  5. Jan 18, 2014 #4
    Ok thank you
  6. Jan 18, 2014 #5


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