2 represents the abscissa point and 3 represents the ordinate point.
Look at the abscissa point first, then at the ordinate point.
Coordinates, mathematical nouns. Refers to the spherical coordinate system established on the celestial sphere to determine the position of a point on the celestial sphere.
There are two basic elements: ① basic plane; Determined by the great circle selected on the celestial sphere; The great circle is called the base circle, and one of the two geometric poles of the base circle is the pole of the spherical coordinate system. 2 points, also known as the origin; It is determined by the intersection of the great circle of the selected pole and the base circle in the coordinate system on the celestial sphere.
Correlation classification
Plane coordinate system is divided into three categories:
1. Absolute coordinate: the specific position of a point on the plane is located with point O as the origin and reference point, and the expression is: A(X, y).
2. Relative coordinates: the specific position of a point on the plane, with the last point of the point as the reference point, expressed as: A(@△X, △Y).
3. Relative polar coordinates: refers to the displacement distance, direction and angle of a point on a plane relative to the previous point, which is specifically expressed as: a (@ d