Why Backpropagation
Why do we use Backpropagation?
For example, consider the expression
Fig. 1
Fig. 2
Fig. 3
Fig. 4
In Fig. 4, Backpropagation gives us the derivative of e with respect to every node (c, d) and input variables (a, b), but Forwardpropagation ONLY gives us the derivative of our output with respect to a single input in Fig. 3 (with respect b only).