# Manipulation of Exterior Derivative

$\mathrm d \left({a b}\right) = a \mathrm d b + \left({\mathrm d a}\right) b$
$\mathrm d \left({a \wedge b}\right) = \mathrm d a \wedge b - a \wedge \mathrm d b$
where $a \wedge b$ is the wedge product.