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.
lim (sqrt(4*n-1)- (sum arctan(1/sqrt(k)), k=1 to n-1)) as n -> infinity
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random