009C Sample Final 2, Problem 4

a) Find the radius of convergence for the power series

$\sum _{n=1}^{+\infty }(-1)^{n}{\frac {x^{n}}{n}}.$

b) Find the interval of convergence of the above series.

Foundations:

Solution:

(a)

Step 1:

Step 2:

(b)

Step 1:

Step 2:

Final Answer:
(a)
(b)

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