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.
integrate 1/pi*(pi-2*[acos(r/2)-r/2*sqrt(1-r^2/4)]) from 0 to 1
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random