Hope this is the right section. I'm having trouble ironing out an apparent inconsistency in matrix trace derivative rules.
Two particular rules for matrix trace derivatives are
\frac{\partial}{\partial\mathbf{X}} Tr(\mathbf{X}^2\mathbf{A})=(\mathbf{X} \mathbf{A}+\mathbf{A} \mathbf{X})^T...
A point charge accelerating through space generates an electric field and radiates energy. But how is this influenced if the point charge is moving along the field lines of an external electric field? Specifically how is calculation of radiated energy effected? Would you add the external field...