Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
sum |2.5/100000 cos(e^(2.5n/100000))| from 1 to 100000
sum |2.5/100000 cos(e^(2.5n/100000))| from 1 to 100000
Natural Language
Math Input
Extended Keyboard