Matrix Calculus

$\mathbf{y}$	$\frac{\delta \mathbf{y}}{\delta \mathbf{x}}$
$Ax$	$A^T$
$x^{T}A$	$A$
$x^{T}x$	$2x$
$x^{T}Ax$	$2Ax$ if $A$ is symmetrical