Take out principal, and just focus on the interest rate. Go here:
Effective Annual Yield Rate of Interest
Enter 4.5 and Press the "Continuous" button. Your answer is 4.60%. Continuous compounding means that the balance in this instant is equal to the balance last instant with a continuously growing rate of interest. The effective annual rate is the actual rate of interest that you earn with compounding interest. Compounding interest is based on what method you use, in this case, you chose continuous. Press the other buttons on my site to see what the effective annual rate would be using other units of time. The more times per year you compound, the greater your effective rate is.
Let me know if you have questions.