Given a smooth function, bezierplot returns a smooth bezier path written in tikz. It finds special points such as extreme points and inflection points and reduces the number of used points.
The upper graph of sqrt(x) used bezierplot, the lower used the built-in plotting function of tikz with 100 samples (no smoothing) and is still quite inexact at the beginning.
For more information read the documentation.
Linus Romer