Backpropagation and Gradient Descent

Backpropagation and gradient descent are two different methods that form a powerful combination in the learning process of neural networks. Let's try to understand the intuition of how this works. Neural networks learn through forward propagation, by using weights, biases, and nonlinear activation functions to calculate a prediction y from the input x that should match the true output y as closely as possible. There are several different loss functions and which one you choose depends on the type of machine learning problem you are facing. The goal of backpropagation is to adjust the weights and biases throughout the neural network based on the calculated cost so that the cost will be lower in the next iteration.