plot 1/N*Sin(N*x/2)/Sin(x/2) and 1/(x*N)*sqrt(2-2*cos(x*N)) at N = 4 between x = 0 and 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.