[ihunter2839]

Not a physicist, so maybe I took the wrong gist away from the article, but - it seems like what they are saying is that systems that are generally modeled by complex equations have always had real valued equivalents that were known.

So it's not that the complex representation isn't a useful mathematical tool, but that it was an alternate representation that was easier to work with. Can you represent a spring mass dampening with all real valued quantities, even if it's a real piece to work with?

[pfortuny]

Sorry because I do not understand your wording very well (English is not my FL), so the answer to your question is yes, you can:

e^(-at)*(A cos(bt) + C sin(bt))

where b is the frequency and a the dampening.

(But you might not be asking for an answer).