If we really want to talk about the essence, it is that functions focus on univariate single-valued functions for elementary mathematics. We study the problem of finding the maximum value and optimizing the maximum value in the univariate single-valued function and some simple proofs. Let me give you an analysis of several test sites for mathematics in the college entrance examination. First of all, there must be geometric proof of trigonometric function and analysis of analytic geometric function. Of course, there should be probability problems. First, three. Basic formula of angular function Remember that trigonometric function is a special function, but it is not out of the category of function. Functional analysis to be analyzed is normal. If it is proved by good geometry, it is some calculation problems. Analytic geometry is still a function problem, just a multi-valued function, but we have solved the derivative of functional analysis easily. Actually, I always thought that the derivative of high school was. Integral is the product of decentralization of college mathematics. Then, if there is a probability problem, remember some basic formulas of permutation and combination. When calculating probability, remember that the denominator is the denominator. When using combinations, your molecules must be combined, so I will introduce so much. Please ask me in the future if you have any questions. I hope I can help you.