Advanced mathematics is to use limit, differential, integral and series to study problems.
Limit and calculus are the basis of foundation.
However, these three important contents are all in the first book.
Mastering the first book directly affects the learning quality of the second book.
For number three, many test sites are in the first volume.
Take a good look
Difficulties: How to determine the point M? Because the side lengths of the left right-angled triangle are 3, 4 and 5