A, for any function, as long as its image is continuous, the zero point of its function has the following properties:
1, when it crosses zero (not even zero), the function value changes sign.
2. All function values between two adjacent zeros keep the same sign.
Second, the method to determine the number of function zeros:
1, judging the number of zeros of quadratic function is generally done by discriminant.
2. For the number of zeros of the quadratic function in the closed interval and the zeros of the quadratic function that cannot be judged by the discriminant, the image of the quadratic function should be combined.
3. The problem of judging the number of zeros of a general function should not only be continuous in the closed interval [a, b], but also f(a)? ? F (b) < 0 can only be determined by combining the image and properties of the function.
Methods and skills of learning mathematics well;
1, listen carefully. If you want to get good grades in math study, you should first pay attention to class and listen carefully to understand what the teacher says. You can write down what the teacher said and review it as the focus of the review.
2. Think independently. Independent thinking is very important for understanding mathematical formulas. For example, when encountering a new problem, how to start thinking, how to choose the right method to solve the problem, and whether you can get the right answer through independent thinking.
3, more hands-on practice. In the review, we should not only prepare the relevant theoretical content, but also do a lot of hands-on practice to consolidate the knowledge we have learned. Different problems will have different solutions. Only by organically combining theory with practical application can we truly and effectively consolidate what we have learned.
4. Be diligent in summing up. When dealing with some problems, we should be diligent in summing up, so that we can quickly get the correct answer by using similar methods in the future. In the final analysis, it is to associate and restore similar situations or similar formulas in the article to general situations to think about problems.
5. Consolidate and test diligently. In reviewing, don't forget to fully consolidate and test what you have learned before. For what you have learned a few days ago, you can make an ideological evaluation every day, which can not only ensure the early ability, but also ensure the fragmentation from the outside to the inside.