Backpropagation is the main learning method that helps artificial neural networks improve at their tasks. At its heart, it's a way for the network to figure out which parts of itself need adjusting to get better results.
Backpropagation is the method we use to optimize parameters in a Neural Network. The ideas behind backpropagation are quite simple, but there are tons of details. Jeremy gives an introduction here! Short tweet here.

Backpropagation computes the gradients of a loss function with respect to the weights in Deep Neural Networks
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The beauty of backpropagation is that it automates the learning process. The network figures out for itself which adjustments will help it improve, rather than requiring humans to program every detail.
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