Diferenciales de funciones trigonométricas

$\parbox{7cm}{ \begin{equation}\quad d (\sin u) = \cos u du \en... ...{equation} \begin{equation}\quad d (\tan u) = \sec^2 u du \end{equation}}$ $\parbox{7cm}{ \begin{equation}\quad d (\cot u) = -\csc^2 u du ... ...ion} \begin{equation}\quad d (\csc u) = -\csc u \cot u du \end{equation}}$