Forward Propagation, Backward Propagation.
element-wise product, with g of l prime z of l. Then to compute the derivatives, dw^l equals dz^l times a of l minus 1. I didn’t explicitly put that in the cache, but it turns out you need this as well. Then db^l is equal to dz^l, and finally, da of l minus 1 is equal to w^l transpose times dz^l. I