:uid: PSfdem
:title: Primary-Secondary Approaches for Frequency Domain Maxwell
:description: 1+1=2, but sometimes it is more useful to think of 2=a+b where a=...
:tooltip:/img/twoab
:tag: em,fdem,finite volume,primary-secondary
:group: simpeg
:license: CC-BY-4.0
:source: https://api.github.com/gists/b10a48dfea9af70aeb52
When solving any math or physics problem, there are usually a few tricks that can take you a long ways. Some of the favorites are: multiplying by 1 (or the identity), adding zero, and breaking things up in to sums (i.e. 2 = a+b, where a=1). I am sure these will be recurring themes among our articles. Here, I am going to spend some time on last point in the context of the frequency domain Maxwell's equations. In this case, 2 = a+b goes by the name of Primary-Secondary. I will develop this for the frequency domain electromagnetic (FDEM) problem, but keep in mind that it is quite general.