Stirling's formula Complete the following steps to find the values of \(p>0\)
for which the series \(\sum_{k=1}^{\infty} \frac{1 \cdot 3 \cdot 5 \cdots(2
k-1)}{p^{k} k !}\) converges.
a. Use the Ratio Test to show that \(\sum_{k=1}^{\infty} \frac{1 \cdot 3 \cdot
5 \cdots(2 k-1)}{p^{k} k !}\)
converges for \(p>2\).
b. Use Stirling's formula, \(k !=\sqrt{2 \pi k} k^{k} e^{-k}\) for large \(k,\) to
determine whether the series converges when \(p=2\). (Hint:
\(1 \cdot 3 \cdot 5 \cdots(2 k-1)=\frac{1 \cdot 2 \cdot 3 \cdot 4 \cdot 5 \cdot
6 \cdots(2 k-1) 2 k}{2 \cdot 4 \cdot 6 \cdots 2 k}\)
(See the Guided Project Stirling's formula and \(n\) ? for more on this topic.)