1. The problem statement, all variables and given/known data Evaluate ∞ ∑ [(e-15 15x) / x!] x=16 15 ∑ [(e-15 15x) / x!] x=0 2. Relevant equations 3. The attempt at a solution The only way I can think of is writing out every term explicitly and adding them on a calculator. Is there any faster way (without having to write out every term explicitly) to calculate the above sums? Thanks for any help!