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Math Help - Roots of Complex Numbers

  1. #1
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    Roots of Complex Numbers

    Can someone please check my work. My instructor said to leave in cis format.

    Find the 4th roots of 1+i

    2^1/8cis(11.25)
    2^1/8cis(25.3)
    2^1/8cis(47.81)
    2^1/8cis(70.31)

    I feel like I'm on the right track...

    Thanks for any help.
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  2. #2
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    Quote Originally Posted by repete View Post
    Can someone please check my work. My instructor said to leave in cis format.

    Find the 4th roots of 1+i
    2^1/8cis(11.25)
    2^1/8cis(25.3)
    2^1/8cis(47.81)
    2^1/8cis(70.31)
    I feel like I'm on the right track.
    The numbers in red are wrong.
    It would be better to use nunbers or degrees.
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  3. #3
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    Ahh ok. It was an arithmetic error. Is this correct?

    2^1/8cis(11.25)
    2^1/8cis(101.25)
    2^1/8cis(191.25)
    2^1/8cis(281.25)

    Thanks that makes more sense.
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  4. #4
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    Quote Originally Posted by repete View Post
    Ahh ok. It was an arithmetic error. Is this correct?
    2^1/8cis(11.25)
    2^1/8cis(101.25)
    2^1/8cis(191.25)
    2^1/8cis(281.25)
    Thanks that makes more sense.
    That of course is in degree form.
    That may be how your instructor wants the answer.

    Here is the number form:
    \frac{\pi}{16},~\frac{9\pi }{16},~\frac{-7\pi }{16},~\&~\frac{-15\pi }{16}
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  5. #5
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    Thanks, I appreciate the help.
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