\(trace(AB)=trace(BA)\) \(trace(ABC)=trace(CAB)=trace(BCA)\) \(\nabla_{A}{trace(AB)}=B^T\) \(\nabla_{A}{trace(ABA^TC)}=CAB+C^TAB^T\) \(\nabla_A|A|=|A|A^{-T}\) \(\nabla_Xtrace(AX^{-1}B)=-(X^{-1}BAX^{-1})^T\)