The function \( f(x)=x e^{x(1-x)},\; x\in \mathbb{R}, \) is:
increasing in \( \left(-\dfrac{1}{2},\,1\right) \)
decreasing in \( \left(\dfrac{1}{2},\,2\right) \)
increasing in \( \left(-1,\,-\dfrac{1}{2}\right) \)
decreasing in \( \left(-\dfrac{1}{2},\,\dfrac{1}{2}\right) \)