User:Dittaeva/Sandbox

Working
$$\sum_{m=1}^\infty\sum_{n=1}^\infty\frac{m^2\,n}{3^m\left(m\,3^n+n\,3^m\right)}$$

Not working, but working at en:watt
$$\mbox{ W} = \frac{\mbox{J}} {\mbox{s}} = \frac{\mbox{N·m}} {\mbox{s}} = \frac{\mbox{kg·m}^2} {\mbox{s}^3} = \mbox{ V·A}$$