Tests

$\displaystyle \leqalignno{ \int v(t)\, dt &= u(t) + C&[3.1]\cr \int v(t)\, dt &= u(t) + H&[3.2]\cr } $
$\displaystyle \leqalignno{ \int v(t)\, dt &= u(t) + C&[3.1]\cr \int v(t)\, dt &= u(t) + H&[3.2]\cr } $