First, the definition of plane rectangular coordinate system.

The two number axes have a common origin and are perpendicular to each other on the plane, forming a plane rectangular coordinate system.

Second, the summary of knowledge points and problems:

1, the symbol of each quadrant coordinate. If the point P(x, y) is in the first quadrant, then x is greater than 0 and y is greater than 0; If the point P(x, y) is in the second quadrant, then x is greater than 0 and y is less than 0; If point P(x, y) is in the third quadrant, then x is less than 0 and y is greater than 0; If the point P(x, y) is in the fourth quadrant, then x is less than 0 and y is less than 0.

2. Coordinate symbols of points on the coordinate axis. The points on the coordinate axis do not belong to any quadrant. The ordinate of a point on the X axis is 0, which means (x, 0), and the abscissa of a point on the Y axis is 0, which means (0, y). The origin (0,0) is on the X axis and the Y axis.

3. Points on the bisector of quadrant angle. If point P is on the bisector of the first and third quadrant angles, then P(m, m); If point P is on the bisector of the second and fourth quadrant angles, then P(m, -m).

4. About the symmetry point of coordinate axis and origin. The symmetry point of point (a, b) about the X axis is (a,-b); The symmetry point of the point (a, b) about the Y axis is (-a, b); The symmetrical point of point (a, b) about the origin is (-a, -b).

5. Distance from point to coordinate axis. The distance from the point (x, y) to the X axis is ∣ y ∣; The distance from the point (x, y) to the X axis is ∣x∣.

Tips and methods to improve junior high school math scores

1, pay attention to the calculation. Doing math problems means paying attention to calculation. Many children lose points in calculation, and there is nothing wrong with solving problems. However, there are mistakes in the calculation process, which lead to the loss of points and affect the overall performance. Therefore, if you want to improve your math scores, you must pay attention to calculation.

2. Details determine success or failure. After the exam, we will find that there are many questions that should not be done wrong, and we lost points because of carelessness. So if you want to improve your math scores, you must pay attention to the details, and you can't lose something you shouldn't lose during the exam.

Divide the calculation so that the particles can be returned to the warehouse. Even if the thinking is correct when solving the problem, you may lose points if you don't pay attention to the details. Compared with test scores, each score represents a person's quality and level. This is the deciding detail.

3. Be good at discovering mathematical laws. If you want to improve your math scores, you must be good at discovering rules in the process of doing math problems. Don't always set formulas rigidly, you can try to change your thinking, which may bring you a different turn for the better, so being good at discovering the law of solving math problems and changing your thinking is also an effective way to improve your math scores.