(integrate 1/(n^3 + 1) from n = 1 to xi) - (sum 1/(n^3 + 1) from n = 1 to xi)

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.