The determinant of a linear transformation measures how much areas/volumes change during the transformation.
Watch the full "Essence of linear algebra" playlist here: goo.gl/R1kBdb
3blue1brown is a channel about animating math, in all senses of the word animate. And you know the drill with YouTube, if you want to stay posted about new videos, subscribe, and click the bell to receive notifications (if you're into that).
If you are new to this channel and want to see more, a good place to start is this playlist: goo.gl/WmnCQZ
This introduces the "Essence of Linear Algebra" series, aimed at animating the geometric intuitions underlying many of the topics taught in a standard linear algebra course.
This course is perfect for any high school student interested in exploring the world of Linear Algebra, which any math and engineering student will face in their college years. Furthermore, this course is perfect for any university and adult learner who wants an intuitive, original, and entertaining explanation of simple and complex Linear Algebra concepts.