(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Calculate the radius of convergence of [itex]\sum_{n=0}^\infty a_{n}z^{2n}[/itex]

let [itex]\sum_{n=0}^\infty a_{n}z^{n}[/itex]with radius R

2. Relevant equations

[itex]\limsup|a_n|^{\frac{1}{n}}=\limsup |\frac{a_{n+1}}{a_n}|[/itex]

3. The attempt at a solution

[tex]\limsup|a_n|^{\frac{1}{n}}=\lim_{k\to\infty}|a_{2k}|^{\frac{1}{2k}}[/tex]

then how to write the "ratio".............

the latex is killin me please help.............

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# Limsupremum calculation horrible difficulty

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