$\mathrm{If} \mathrm{L}=\underset{x\to 0}{\lim }\frac{{\mathrm{e}}^{-{\mathrm{x}}^2/2}-\mathrm{cosx}}{{\mathrm{x}}^3\mathrm{sinx}}, \mathrm{then} \mathrm{the} \mathrm{value} \mathrm{of} \frac{1}{\left(3\mathrm{L}\right)} \mathrm{is}$______

$\begin{array}{l} \underset{x\to 0}{\lim } \frac{e^{-x^2/2}-\cos x}{x^3\sin x} \\ =\underset{x\to 0}{\lim } \frac{\left(1-\frac{\left(x^2/2\right)}{1!}+\frac{{\left(x^2/2\right)}^2}{2!}\right)-\left(1-\frac{x^2}{2!}+\frac{x^4}{4!}\right)}{x^3\left(x-\frac{x^3}{3!}\right)}\\ = \underset{x\to 0}{\lim } \frac{\left(\frac{x^4}{8}\right)-\left(\frac{x^4}{24}\right)}{x^4\left(1-\frac{x^2}{3!}\right)}=\frac{1}{12}\end{array}$