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Calculators (-i)^4 = Domain Error?

  1. Apr 18, 2012 #1
    I'm curious if anyone knows why my calculator would return "Domain Error" when calculating (-i)^4 on my TI-36X Pro?

    ((-i)^2)^2 works just fine on the machine, and (-i)^4 works just fine on my TI-83 Plus.

    Any ideas?
  2. jcsd
  3. Apr 20, 2012 #2


    Staff: Mentor

    The only thing I can think of is that the calculator might be using logs to calculate the value. The following is an identity for real x > 0.

    xn = (eln(x))4 = e4ln(x).

    It's possible that it is programmed to be able to calculate i2 and (-i)2, but for other powers it uses a different algorithm

    Consult your user manual - it might have some information about the domains of the functions it can calculate. I'm sur they have a web site, and they might have a site where you can ask questions about the specific models.
  4. Jun 4, 2012 #3
    Thank you, Mark. I apologize for not recognizing your post sooner! I checked my user manual and it only says that it cannot compute i to a power greater than 3.
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