First, all kinds of derivatives are necessary, and many functions must be known and can be derived (including what sec high school didn't mention at all, and universities directly used it). The definition and limit of high school derivatives are also very important. These things have been common since college.
Secondly, L'H?pital's law may occasionally meet the grand finale of derivative in the college entrance examination, but it has a place in higher mathematics and has a certain foundation.
Third, integration. Universal formula, the formula of product and difference product may be the forbidden area of high school. High school students are too wet and cross the line. However, these things are deadly weapons in the integration of advanced mathematics, and you can't do anything without their integration. It is worth mentioning that there is a kind of integral in high school that is solved by geometric meaning (graphic area), which may also be involved in universities (but generally it can be solved by substitution integral).
Fourth, there is a subject in college mathematics called probability theory (as compulsory as advanced mathematics and calculus). A lot of probability knowledge and various distributions (especially orthogonal distribution) that have been used in senior high school are used, so the probability-related problems in senior high school mathematics must be learned well.
Fifthly, determinant matrix in linear algebra may be studied as an elective course in senior high school mathematics in some places.
Sixth, high school mathematics involves series and such as dislocation subtraction, which may be mentioned in the chapter of university series.
I think that's about it. In fact, high school mathematics is far from college mathematics. After all, college mathematics deals with all kinds of famous mathematicians, and the high-end atmosphere is bound to be higher, so there is not much contact. In fact, in real college mathematics, many high school mathematics things are not needed. College mathematics mainly focuses on differential, integral, probability and matrix.