Hi @saifkhanengr,
DLS came first and then MLS was updated, so there’s chance that the convention of notations by Andrew might have changed in MLS. While taking DLS, I’d recommend to not connect it MLS because of that reason, and instead follow the conventions as mentioned in DLS for the purposes of quizzes and assignments.
Additionally, going over the Standard notations for Deep Learning, found here, will help you better understand these concepts.
Best,
Mubsi