Space vector is a mathematical term, which refers to the quantity with size and direction in space.

The size of a vector is called its length or modulus. A vector with a length of 0 is called a zero vector and recorded as 0. A vector with a modulus of 1 is called a unit vector. A vector with the same length and opposite direction as vector A is called the inverse vector of A .. and it is called-A. A vector with the same direction and the same modulus is called an equal vector.

Three coordinate planes divide the space into eight parts, and each part is called a divination limit. The divination limit including X-axis positive semi-axis, Y-axis positive semi-axis and Z-axis positive semi-axis is called the first divination limit, and the other second, third and fourth divination limits are determined counterclockwise above the xoy plane. The parts below the first, second, third and fourth hexagrams are called five, six, seven and eight diagrams respectively.

Mathematically, solid geometry is the traditional name of three-dimensional Euclidean space geometry-because in fact, this is roughly the space in which we live. Generally as a follow-up course of plane geometry. Stereo measurement involves volume measurement of different shapes: cylinder, cone, frustum, cone, cone, cone, cone, cone, cone, cone, cone, cone, cone, cone, cone, cone, cone, cone, cone. Ball, prism,? Wedge? Bottle caps or something.

Pythagoras School studied spheres and regular polyhedrons, but before Plato School began to study them, people knew little about pyramids, prisms, cones and cylinders. Eudoxus established their measuring method and proved that a cone is one third of the volume of a cylinder with equal bottom and equal height, which may be the first proof that the volume of a sphere is proportional to the cube of its radius.