To understand the partial derivatives we need to understand derivatives which is a case of partial derivatives

Derivatives is a function that take single parameters or single variable X.

Partial derivatives could have many parameters and variables and this is what we need to understand ultimately because in a neural network which have multiple inputs. Each input gets multiplied by the corresponding weight (a function of 2 parameters), and they get summed with the bias (a function of as many parameters as there are inputs, plus one for a bias).

Let’s start with a simple function and discover what is meant by “impact.” A very simple function y=2x , which takes x as an input: