a=x^2+x+1,b=x^2-1,x=2x+1,c^2 = a^2+b^2-2ab*cos(pi/6)

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.