Hi,

I’m not quite clear on why at 6:20 mark, professor Ng removed the negative sign from the front of the summation.

I think I followed his explanation when he said that we removed the negative sign (-) because, want to minimize the cost function J(w,b), instead of maximizing the likelihood (referring to the introduction of negative sign (-) at 4:08 mark).

But, I am confused because, throughout first week and, up to this video, the cost function over m example has always had (-1/m) in front of the summation, including the pseudocode in Vectorizing Logistic Regression video. Even the Machine Learning Specialization has always shown the negative sign (-) in front of the cost function and loss function when the logistic regression is discussed.