- #1

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Ʃ(0,inf) (n(n-1)(z+5i)^n)/n

Using the ratio test lim n-> |an+1/an|

I was able to get it down to lim n->|n(z+5i)/(n-1)| which gave |inf/inf| = 1, which means the test fails. What do I do to properly solve this? :(

- Thread starter sgonzalez90
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- #1

- 6

- 0

Ʃ(0,inf) (n(n-1)(z+5i)^n)/n

Using the ratio test lim n-> |an+1/an|

I was able to get it down to lim n->|n(z+5i)/(n-1)| which gave |inf/inf| = 1, which means the test fails. What do I do to properly solve this? :(

- #2

Office_Shredder

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[tex] \lim_{n\to \infty} |\frac{n(z+5i)}{n-1}| = |z+5i| \lim_{n\to \infty} \frac {n}{n-1} [/tex]

- #3

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ROC

= |z+5i| < inf?

:D

= |z+5i| < inf?

:D

- #4

Office_Shredder

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