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(pi*sqrt(n² + n)) = (-1)^n * cos(n*pi - pi*sqrt(n² + n)) true or false
cos(pi*sqrt(n² + n)) = (-1)^n * cos(n*pi - pi*sqrt(n² + n)) true or false
Natural Language
Math Input
Extended Keyboard
