title: Using a Math Library in the iOS View Controller
body: <p>I am creating a view controller for a calculator view. This calculator requires the use of a lot of heavy duty financial math. I encapsulated most of the calculations into a few functions, should these functions be left in the view controller or should I create a separate library and use them there? </p>
  
  <p>If I do create a separate library, do I connect it using #import or do I use Objective-C categories?</p>