I’m reading a Neural Networks Tutorial. In order to answer my question you might have to take a brief look at it.
I understand everything until something they declare as "chain function":
It’s located under 4.5 Backpropagation in depth.
I know that the chain rule says that the derivative of a composite function equals to the product of the inner function derivative and the outer function derivative, but still don’t understand how they got to this equation.
Please read the article and try to only use the terms and signs that are declared there. It’s confusing and tough enough anyway, so I really don’t need extra-knowledge now. Just use the same "language" as in the article and explain how they arrived to that equation.