There are too many topics. I'm doing a few things.

I'm glad to answer your question. You don't need to increase any wealth. As long as it is adopted in time, it is the best reward for us.

. If there is anything that the questioner still doesn't understand, you can ask questions at any time and I will try my best to answer them. I wish you progress in your study. Thank you.

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The most important thing in learning advanced mathematics is perseverance. In fact, no matter what kind of subjects, except for many examples in books, you should usually do more exercises by yourself. You should challenge every type and every difficulty. Don't be discouraged if you can't do it. Ask others more. What you learn from others is your own, and then you will have a good effect by learning it yourself. Therefore, it is important to accumulate experience. The best way is to often help others solve problems and increase their own experience and experience in doing problems!