If you want to really understand how nonlinear regression works, you will need to learn matrix algebra and study advanced math books. But you can use nonlinear regression effectively so long as you understand the basic principles of regression.
•Why minimize the sum-of-squares?
•How nonlinear regression works
•The need for unequal weighting in nonlinear regression
•How standard errors and confidence intervals are computed
•How confidence and prediction bands are computed
