3.56: Small change for $y = x^{2}\tan(x/2)$

Given that $y = x^{2}\,\mathrm{tan}\dfrac{x}{2}$, use calculus to find the approximate change in $y$ as $x$ increases from $\dfrac{\pi}{3}$ to $\dfrac{\pi}{3} + h$, where $h$ is small.