$\displaystyle \oint Bdl=\mu\int JdA+\mu\frac{{d}}{dt}\int EdA$
$\displaystyle \int(curlB)dA=\mu\int divJdV+\mu\frac{{d}}{dt}\int divEdV$
how to go from the above integral equation to the bottom equation
$\displaystyle
curlB=\mu\varepsilon\frac{{dE}}{dt}+\mu J
$