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.
cos^(-1)((4 sqrt(5) (5-2 sqrt(5))^(1/4))/(1+20 sqrt(5-2 sqrt(5))))
cos^(-1)((4 sqrt(5) (5-2 sqrt(5))^(1/4))/(1+20 sqrt(5-2 sqrt(5))))
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random