Cylindrical surface: the surface formed by the parallel movement of straight lines along a fixed curve. The straight line is called the straight generatrix of the cylindrical surface (this picture shows that the generatrix is parallel to the Z axis? Cylinder), and the fixed curve is called the directrix of the cylinder (this figure is the directrix x parallel to the XOY plane? +Y？ =R？ )。 When the directrix is a circle, the resulting cylinder is called a cylinder; Especially if the straight generatrix is perpendicular to the plane of the circle, the resulting cylinder is called a straight cylinder, and a straight cylinder can also be regarded as a moving straight line parallel to the alignment and moving a certain distance parallel to the alignment. A fixed line is its axis and a fixed distance is its radius. By the ellipse on the plane, respectively? Hyperbolic summation? Cylinders whose parabolas are directrix are called elliptic cylinders, hyperbolic cylinders and parabolic cylinders. Their equations are all quadratic, collectively called quadratic cylinders. There are only two variables in the spatial cartesian coordinate system? Quadratic equations generally always represent a quadratic cylinder or two planes.

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Application of Cylindrical Surface in Modern Life —— Cylindrical Mirror

Cylindrical mirror is mainly used to change the design requirements of imaging size. For example, a point spot is converted into a line spot, or the height of an image is changed without changing the required width.