Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Community Proposals
Community Proposals
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »
Q&A

Post History

71%
+3 −0
Q&A Find the value of $\sum_{k=1}^\infty\frac{k^2}{k!}$

3 answers  ·  posted 5mo ago by Snoopy‭  ·  last activity 5mo ago by Derek Elkins‭

#2: Post edited by user avatar Snoopy‭ · 2024-08-06T21:28:30Z (5 months ago)
  • Find the value of $\displaystyle \sum_{k=1}^\infty\frac{k^2}{k!}$
  • Find the value of $\sum_{k=1}^\infty\frac{k^2}{k!}$
#1: Initial revision by user avatar Snoopy‭ · 2024-08-06T21:28:16Z (5 months ago)
Find the value of $\displaystyle \sum_{k=1}^\infty\frac{k^2}{k!}$
**Problem.** Find the value of $\displaystyle \sum_{k=1}^\infty\frac{k^2}{k!}$. 


**Note**: For most convergent series, proving convergence significantly differs from calculating their values, if it is even possible. One has tools such as [convergence tests](https://en.wikipedia.org/wiki/Convergence_tests) to determine whether a given series converges. On the other hand, finding the value of a convergent series is often highly nontrivial, as it frequently requires computing the value in a specific context. For calculus beginners, computing the values of convergent series can be particularly challenging, as they often struggle to place the problem within a broader context.

I will write my answers below. Answers from different perspectives are welcome.