# Bernstein polynomial: function to approximate

I am studying the Bernstein polynomial with Matlab. I wish to code the example in the wikipedia page of Bernstein polynomial, but I can not figure out the explicit form of the red function (see figure).

This animation was created with Maple 9.5 and Jasc Animation Shop. It shows Bernstein polynomials approximating $$x \sin(\frac 72\pi {\sqrt {x}})$$ (chosen for purely aesthetic reasons).
Although, it appears that the true formula is $$-x \sin(\frac 72\pi {\sqrt {x}})$$.