the professor was just there to fulfill his contractual obligations
he didn't teach much
he reviewed the very basic material that most in the class have already mastered and spent very little time on the newer material
he talked ~40 minutes about dimensional analysis and basic differential calculus with only 30 minutes to spare for lines and planes in R3, the cross product and the dot product
then he talks about a little used vector equation for a plane that does not involve a normal vector
it's not published in the textbook and i can't find it anywhere else online
is that some sort of recipe