f^{(n)}(x)=\left\{\begin{array}{ll}
- x\sin(x + \frac{n \pi}{2})-n\sin(x + \frac{(n-1) \pi}{2}) &: x < 0\\
x\sin(x + \frac{n \pi}{2})+n\sin(x + \frac{(n-1) \pi}{2}) & : x>0 
\end{array}\right.