nonlinear regression

A form of mathematical model that reflects results in a curve between two variables (X & Y) rather than a straight-line relationship as in the case of a linear regression, which are usually simpler with expression such as Y= a + bx. The main characteristic of a non-linear regression is that the prediction equation does not linearly depend on the unknown parameters. This type of regression uses functions such as trigonometry, logarithm and exponential.