How to multiply two summations together?

How to multiply two summations together?

• Questions are typically answered in as fast as 30 minutes

Plainmath recommends

• Get a detailed answer even on the hardest topics.
• Ask an expert for a step-by-step guidance to learn to do it yourself.

Melinda Olson
For example,
$$\displaystyle{\left({\sum_{{k}}^{\infty}}{a}_{{{k}}}\right)}{\left({\sum_{{k}}^{\infty}}{b}_{{{k}}}\right)}={\sum_{{n}}^{\infty}}{\sum_{{k}}^{\infty}}{a}_{{{k}}}{b}_{{{n}-{k}}}$$
Have a similar question?
Tamara Donohue
How exactly did you obtain your result?