Introduce new knowledge of backpack production

Plane cartesian coordinate system

If you have two number lines that are perpendicular to each other and have a common origin in the plane, you have a planar cartesian coordinate system.

Any point P in the coordinate plane has a unique pair of ordered real Numbers (X, Y) corresponding to it; Conversely, any pair of ordered real Numbers (X, Y), in the plane, will be able to specify a unique point whose coordinates are (X, Y). So, a planar cartesian coordinate system, you can combine Numbers with shapes.

The knapsack is a solid, but the single component of the knapsack is in the same plane.In order to draw the shape of the knapsack member, the knapsack manufacturer can first measure the number related to the switch with a ruler. By these Numbers, the points related to the switch can be determined. The surface shape of the knapsack member can be drawn by connecting these points with a straight line or a smooth curve. Then, we use the compasses along the edge of the shape of the member surface to enlarge in a unit of the length of the paper mouth, and we get the shape of the backpacking member. This is the principle and method of drawing up the knapsack components.