first question:

dr ng explain the polynomial regression but the gradient descent will change which i mean that the derivative will change ok then when will this course explain that or should i learn it from another course or this course will cover that but later on, and the second question?

second question: what about the normalization ok i learn alot of feature scalling like mean, z-score, mini, max which one should i apply and when i normalize the training set the parameters will be normalize that means i should denormalize the parameters right to predict the output is that correct and please if that correct what is the roles to denormalize the parameters and thanks