$$\begin{array}{l}P1＝{\displaystyle \underset{k＝2}{\overset{\infty }{\prod }}1-\frac{1}{k^2}}，\\ P2＝{\displaystyle \underset{k＝2}{\overset{\infty }{\prod }}\frac{k^2}{k^2-1}}．\end{array}$$

$$P＝{\displaystyle \underset{k＝1}{\overset{10000}{\prod }}\frac{e^{kx}}{x}}．$$

$$\begin{array}{l}P1＝{\displaystyle \underset{k}{\prod }k}，\\ P2＝{\displaystyle \underset{k}{\prod }\frac{2k-1}{k^2}}．\end{array}$$