Practice Exercises for advanced topics

Please add exercises for the advance Mathematics topics.

The quantum mechanics playlist does not contain a section discussing Dirac notation; same with 1/2-spin states unless I missed it. (I'm going to check if there is any reference to the Stern-Gerlach experiments)

 I'm currently learning Linear Algebra, Multivariable Calculus, and Diff Eq in order to 'cheese' my final semester in community-college. It would be nice to have supplemental exercises necessary to learn these topics. Otherwise i'll have to buy a text book; effectively rendering Khan Academy's services obsolete. 

I appreciate and idolize you guys! I love Math and truly hope to continue learning from Khan Academy. However, the mission to provide a free, quality education to everyone is being ignored. In terms of the Math playlists, this begins with the lack of exercises for Multivariable Calculus and Linear Algebra. The integrity of Khan Academy's claim is severely damaged due to this obvious omission of exercises, as well as the blatant disregard towards the value of practicing the discussed concepts.

I've noticed that this has been the case for a significant amount of time in spite of the several requests being made here. Hopefully the students that still require supplemental practice will receive an email once the playlist is added.

Thanks for reading!

Keep on keepin' on.