I'm in a bad mood recently, because I can't understand the chapter on mathematical functions, and I can't find a way out and tips. What should I do? Is the function really difficult to learn? thank you Function can be understood as a subject that quantifies the causal relationship of things with numbers, such as the causal relationship between current and voltage, the causal relationship between speed and displacement in physics, and the causal relationship (the cause without result is not called cause). Corresponding to a function means that for every value (cause) of x, there is a y (result) corresponding to it. For one reason, it is logically impossible to have two results at the same time (at the same time), that is, there can only be one Y and X to correspond, so the concept of mapping comes out. Mapping is a special correspondence between two sets, that is, if any element in set A follows certain correspondence rules, mapping is the study of causality (I personally understand), so it is a function to quantify the elements in set A and set B (that is, to express some attributes of things by numbers). As long as you understand the essence of a function, other specific functions are easy to say. The most stupid way is to grab a function, draw all the situations by exhaustive method, and naturally find the law.

Functions have three content definitions (as mentioned above) and other properties (periodic monotonicity parity) that will be learned later. And the details of basic elementary functions. Five trigonometric inverse trigonometric functions, power function, exponential function and logarithmic function are like 1234 in mathematics. The basic important properties of functions that must be mastered are interspersed in these five basic elementary functions for learning.

As long as you understand the essence of function (that is, China's Tao), then the rest is pure (technical) research, such as attributes, images and so on