Square root of complex

Discussion in 'Math' started by TheSpArK505, Dec 30, 2014.

  1. TheSpArK505

    Thread Starter Member

    Sep 25, 2013
    92
    0
    Hello guys,

    I wnat to take the square root of a complex over complex, i have set my calculator(casio fx-991ES plus)
    to complex but when i try to calculate it gives me math error!!!! is there any set ups or its impossible to take square root of complex
     
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    Don't know about your particular calculator capabilities.
    It's not that difficult a computation - if that's your main concern.
    Starting with the original complex ratio value as a single value polar form, the square root is readily determined - as you presumably know. If your calculator can do the complex division and display the result in polar form the last step is relatively easy.
    The polar form of the square root
    \sqrt {A \angle {\pm \theta}} =\sqrt {A} \angle\pm \frac{\theta}{2}
     
    Last edited: Dec 31, 2014
  3. TheSpArK505

    Thread Starter Member

    Sep 25, 2013
    92
    0
    Thanks it's easier now;)
     
  4. MrAl

    Well-Known Member

    Jun 17, 2014
    2,425
    490
    Hi,

    It might also help sometimes to remember:

    sqrt(A/B)=sqrt(A)/sqrt(B)
     
  5. russ_hensel

    Well-Known Member

    Jan 11, 2009
    818
    47

    In the square root you can add 2pi to theta ( one or more times ) before dividing the angle to get other square roots ( here just 2 in total)> More for cube roots, 4thf roots, etc.
     
  6. amilton542

    Active Member

    Nov 13, 2010
    494
    64
    Yeah it's called De Moivre's theorem.
     
  7. Motanache

    Member

    Mar 2, 2015
    70
    4
  8. WBahn

    Moderator

    Mar 31, 2012
    17,737
    4,789
    Because some people want to actually learn the concepts behind the math instead of just letting a tool written by someone else do their thinking for them.
     
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