where the higher order terms not shown are negligible because is small, and is simply the boost matrix in the x direction. The derivative of the matrix is the matrix of derivatives (of the entries, with respect to the same variable), and it is understood the derivatives are found first then evaluated at ,
where the higher order terms not shown are negligible because is small and is simply the boost matrix in the x direction The derivative of the matrix is the matrix of derivatives (of the entries with respect to the same variable) and it is understood the derivatives are found first then evaluated at 