However this is not the case with non-linear functions. A non-linear function does not have a constant slope. Consider the non-linear function shown below. What is the slope at some point such as P?

where x, y, and w can be vectors, the f_i() functions can be linear or nonlinear, and w_i is the ith element of the w vector. Examples of linear function approximators include: Lookup table There is a ...

Almost periodic functions serve as a powerful conceptual framework in analysing differential equations whose coefficients or forcing terms exhibit recurrent behaviour over time.