question about this part: > f(x) has to be a non-linear function, otherwise the neural network will only be able to learn linear models. I thought one of the

question about this part: > f(x) has to be a non-linear function, otherwise the neural network will only be able to learn linear models. I thought one of the most common functions was relu, which is linear (but cuts off to 0 for x values below 0) https://en.wikipedia.org/wiki/Rectifier_(neural_networks) https://en.wikipedia.org/wiki/Rectifier_(neural_networks)