suppose Σan xⁿ be a power series and an= the number of divisors of n⁵⁰. Then what will be the radius of convergence of this power series? Thanks in advance . regards.
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Originally Posted by sorv1986 suppose Σan xⁿ be a power series and an= the number of divisors of n⁵⁰. Then what will be the radius of convergence of this power series? Hint $\displaystyle 1\leq a_n\leq n^{50}\Rightarrow 1\leq a_n^{1/n}\leq (n^{1/n})^{50}$ . Now, apply the Sandwich Theorem.
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