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Math Help - radius of convergence

  1. #1
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    radius of convergence

    How do you find the radius of convergence for power series like the following:

    \sum_{n=1}^\infty (1/n!)*(z-1+i)^{2n}


    \sum_{n=0}^\infty z^{2n+1}
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  2. #2
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    Quote Originally Posted by grad444 View Post
    \sum_{n=1}^\infty (1/n!)*(z-1+i)^{2n}
    Hint: Use the fact that (n!)^{1/n} \to \infty and now use the root test.

    \sum_{n=0}^\infty z^{2n+1}
    Again use the root test here.
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