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> For which values of $x$ is $$ \sum\_{n=1}^{\infty} \frac{(2n)!\,x^n}{2^{2n}(n!)^2}$$ convergent or divergent? 
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• I tried $x=-1$ and i tested it by using [Comparison Test](https://en.wikipedia.org/wiki/Comparison_test) and [Ratio Test](https://en.wikipedia.org/wiki/Ratio_test) but that was diverge. This series is not absolutely converge for $x=-1$ if I am right. 

• Any suggestions?