Machine Learning, Deep Learning, Backpropagation, Artificial Intelligence, Differential Calculus.
derivative of the cost w.r.t to the weights W[l-2] . Congratulations! Don’t be demotivated if you did not understand it for the first time,you are not alone.I will love to have a discussion in the comment section:D I remember when I was trying to do math behind Backpropagation,I did not understand