I heard that calculators can be used in physics competitions. The requirements of the competition for students are that the initial test is the basis of your high school mathematics and physics, and the difficulty of the semi-finals is close to that of the university. Read relevant competition books. Sometimes their competition group will go to the university to listen to the professor's lecture. Infinitesimal method, as a classical method to solve physical problems, is of course to be mastered, and it will be of great help to you when used in some problems.