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Homework Help: Question regarding complex numbers

  1. Feb 8, 2015 #1
    1)If a= cosα + i sinα and the equation az2 + az +1 =0 has a pure imaginary root, then tanα=?

    2) cosα+isinα=e , quadratic formula

    3) What i tried to do was,i put a constant real number and tried to solve it and used demoivres theorem, although the answer is getting weirder and weirder.
  2. jcsd
  3. Feb 8, 2015 #2


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    You need to show your work.
  4. Feb 8, 2015 #3


    Staff: Mentor

    Yes, please show what you have done, Mohsin Hussain.

    This is an important piece of information --
  5. Feb 13, 2015 #4
    sorry for bothering, it was a fairly easy one. didnt read the word "purely". Thanks.
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