How to do it?

[rupa]

\(\displaystyle \displaystyle \sum_{m,n \geq 0} \dfrac{mn}{(m+n)!} \)

 

[Steven G]

\(\displaystyle \displaystyle \sum_{m,n \geq 0} \dfrac{mn}{(m+n)!} \)

I take it that m and n are integers?? What are we summing over? Or are we summing over all m,n combinations where m and n are positive integers?

 

[stapel]

How to do it?

\(\displaystyle \displaystyle \sum_{m,n \geq 0} \dfrac{mn}{(m+n)!} \)

What is the "it" what you're needing to "do"? What were the instructions? What have you tried? Where are you stuck?

Please be complete. Thank you!