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.
(r+1)/sqrt l (EllipticF(arccos(1-(2l)/(sqrt2+r+l)),(2+3r/l)/4)),where r=(cbrt(108+12sqrt69)+cbrt(108-12sqrt69))/6,l=sqrt(3r^2-1)
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random