This question doesn't lend itself well to plain text, so I LaTeX'd and screenshotted it. I'll do my best with the alt text.
![Is there a way of writing the expression<br>\[ \sum_{n=1}^m f(n) \]<br>in a way that omits the term where $n=a$?</p><p>I know it could be written as<br>\[ \left( \sum_{n=1}^m f(n) \right) - f(a) \]<br>but this doesn't work when $f(a)$ is undefined. Is there a way of writing the expression<br>\[ \sum_{n=1}^m f(n) \]<br>in a way that omits the term where $n=a$?</p><p>I know it could be written as<br>\[ \left( \sum_{n=1}^m f(n) \right) - f(a) \]<br>but this doesn't work when $f(a)$ is undefined.](https://social.jlamothe.net/photo/13528377976a61653463c9a386467268-1.png)
#math #maths #mathstodon #AskFedi
![Is there a way of writing the expression<br>\[ \sum_{n=1}^m f(n) \]<br>in a way that omits the term where $n=a$?</p><p>I know it could be written as<br>\[ \left( \sum_{n=1}^m f(n) \right) - f(a) \]<br>but this doesn't work when $f(a)$ is undefined. Is there a way of writing the expression<br>\[ \sum_{n=1}^m f(n) \]<br>in a way that omits the term where $n=a$?</p><p>I know it could be written as<br>\[ \left( \sum_{n=1}^m f(n) \right) - f(a) \]<br>but this doesn't work when $f(a)$ is undefined.](https://social.jlamothe.net/photo/13528377976a61653463c9a386467268-1.png)
#math #maths #mathstodon #AskFedi
Mathematics Channel reshared this.
![Is there a way of writing the expression<br>\[ \sum_{n=1}^m f(n) \]<br>in a way that omits the term where $n=a$?</p><p>I know it could be written as<br>\[ \left( \sum_{n=1}^m f(n) \right) - f(a) \]<br>but this doesn't work when $f(a)$ is undefined. Is there a way of writing the expression<br>\[ \sum_{n=1}^m f(n) \]<br>in a way that omits the term where $n=a$?</p><p>I know it could be written as<br>\[ \left( \sum_{n=1}^m f(n) \right) - f(a) \]<br>but this doesn't work when $f(a)$ is undefined.](https://social.jlamothe.net/photo/13528377976a61653463c9a386467268-1.png)
Mathematics Channel reshared this.
Darcy Casselman
in reply to Jonathan Lamothe • • •Sensitive content
math.stackexchange.com/questio…
I'm gonna miss stack exchange.
Summation with exclusion
Mathematics Stack ExchangeJonathan Lamothe likes this.
imadeddinzaqout613
in reply to Jonathan Lamothe • • •