1. In the process of learning advanced mathematics, it is extremely normal to encounter something that you can't understand. At this time, what you need is to check some basic elementary mathematics knowledge (pay attention to systematic mastery) and go back to your own research (be sure to study hard and have perseverance. For example, it took me 1 months to understand Taylor's formula, so there is no reason why you can't understand it.
2. In the process of self-study, the only way to test the effect is to do the questions, which is also an effective way to consolidate the learning results. If you don't do the problem, even if your memory is good, it is difficult to thoroughly digest the concepts you have learned. When I taught myself electricity, I read six concepts one day and almost forgot them the next day. After that, I joined the process of doing the problem when I taught myself, so I was able to use it all in just a few days)
The most important thing to learn advanced mathematics is to know what it is and why. Almost every theorem in the book "Advanced Mathematics" is derived in detail, and the derivation process must be "written" under the condition of thorough understanding (unlike rote learning in liberal arts, it may take several days), so that there will be a very smooth feeling in the process of doing the problem.
Mathematics is a science, not as "dead" as liberal arts. When you do the problem, you must do whatever you want, and you must never copy the steps in the solution. I never copy the math teacher's steps in class. I think and make my own process, unlike taking notes in Chinese class.
In addition, there is a video lecture on advanced mathematics in Cai Gaoting. When searching for videos online, an address /u98 /u98/v_MzI3NDMzOTE.html will be provided first.