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You can learn mathematics in junior high school, but you can't learn functions and don't understand them in senior high school.
The function of mathematics in junior high school is only a linear function, and other knowledge and functions are closer to solving quadratic equations, and drawing is not needed to solve quadratic functions. Although the linear function also mentioned drawing, it is still in the primary stage. Generally speaking, most of the knowledge of junior high school mathematics is something you can see (that is, it is not abstract), but senior high school mathematics is about to come into contact with some abstract mathematics, such as the collection taught before teaching senior high school functions. For expressing the concept of function in the form of set, he can't list what he has learned one by one like junior high school mathematics knowledge, but he can see that the concept of function is expressed in the form of set, and the range between the definition and value of function is measured.

Let's talk about the function of high school and how to study separately: (I think the following is useful for you, so you might as well top it)

Although high school functions are expressed in the form of sets, we feel that many kinds of one-to-one sets are functions, but you don't need to care so much here. You just need to understand: the three elements that make up a function (definition domain, one-to-one correspondence, also called resolution function and range), know that the values defined by a function can only get a unique value (included in the range) through one-to-one correspondence, but a value in the range is one-to-one correspondence.

1。 Corresponding to the definition domain, we often examine the definition domain of the function, and we can judge the definition domain of the function by seeing how to make the distinguishing function meaningful (this uses the previous knowledge, such as: the number under the root sign cannot be negative, the denominator cannot be zero, and so on).

2。 Corresponding to the range, we often investigate how you can solve the range according to the resolution function by defining the range.

3。 For the resolution function, this is the focus of high school functions, which will be discussed below.

In addition to the three elements of a function, the next step is to learn the monotonicity of the function, the maximum value of the function, the periodicity, symmetry, translation contraction, the image of the function and so on. It depends on your understanding of how it defines these concepts in teaching and how to use them skillfully.

The next thing to talk about is the resolution function. Although there are many types of functions, I mainly learned some elementary functions of piecewise functions in high school. Next, I will mainly talk about several elementary functions: (These functions can finally be understood through drawing exercises. Drawing pictures can make you understand many properties of functions and the characteristics of various functions vividly, which is very important. I hope you can pay attention to it. )

Quadratic function: Quadratic function is parabola, and the main things to learn are: symmetry axis and vertex of parabola. Understand that parabolas are monotonous on both sides of the axis of symmetry.

Exponential function: y = a x When learning this kind of function, it is very useful for you to draw the corresponding correct graph. What needs to be mentioned here is: pay attention to (0, 1).

Logarithmic function: Logarithmic function and exponential function are a pair of inverse functions (inverse functions are symmetrical about the proportional function y=x), so pay attention to this (1, 0).

Power function: y = x a, for this kind of function, we should pay attention to the difference between it and exponential function: y = a x, and learn more about a = 1, 2,3,5,-1, -2, -3,1/2,65438.

Sine and cosine function in trigonometric function: For this kind of function, we often investigate its range and period, and when learning this kind of function, we will mention the translation and contraction of the function.

That's all for now. I hope this will help you solve the current situation and don't forget to support my reply.