n*(1-x)^2+2*k*x^2(1-x)^2 -x^2-k*(1-x)^4 where n=4, k=3

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.