Introduction of rectangular coordinate system in mathematics;
Two number axes perpendicular to each other on the same plane and having a common origin form a plane rectangular coordinate system, which is called rectangular coordinate for short.
Usually, the two number axes are placed in the horizontal position and the vertical position respectively, and the right and upward directions are the positive directions of the two number axes respectively. The horizontal axis is called X axis or horizontal axis, the vertical axis is called Y axis or vertical axis, and the X axis and Y axis are collectively called coordinate axes.
Their common origin O is called the origin of rectangular coordinate system, and the plane rectangular coordinate system with point O as the origin is recorded as the plane rectangular coordinate system xOy.
Extended data:
Some properties of coordinate system:
Points on the 1. coordinate plane have one-to-one correspondence with ordered real number pairs.
2. The horizontal and vertical coordinates of the points on the bisector of the quadrant angle are equal.
3. The horizontal and vertical coordinates of the points on the bisector of the second and fourth quadrants are reciprocal.
4. Move up and down a little, and the abscissa remains unchanged, that is, the abscissa of the point on the straight line parallel to the Y axis remains unchanged.
5. The abscissas of the points on the Y axis are all 0.
6. The ordinate of the point on the X axis is 0.
7. The points on the coordinate axis do not belong to any quadrant.
8. The abscissa of the point symmetrical about the X axis remains unchanged, and the ordinate becomes the reciprocal of the original coordinate. or vice versa, Dallas to the auditorium
9. The horizontal and vertical coordinates of a point symmetrical about the origin are the reciprocal of the original coordinates.
10, when symmetrical with x, x remains unchanged and y becomes the opposite number.
1 1. When it is symmetrical with Y, Y remains the same and X becomes the opposite number.
12. When y and x are symmetrical with the origin, they become opposite numbers.