A point or line that, when moved along a certain path (called the directrix), creates a new shape.
Also called a generator.
For example, a line moving in a circle traces out a cylinder.
In the applet above, press "Run". The generatrix is the line on the right. As it moves at a fixed distance from the left line,
it traces out a
right circular cylinder.
The path it follows is a circle. The path followed in the way is called the
In another example, a point moving at a fixed distance from a central point will trace out a circle.
The moving point is the generatrix (or generator) of the circle.
A cylinder is a closed solid that has two parallel (usually circular) bases connected by a curved surface. It can be a right cylinder or an oblique cylinder.
A cylinder can be thought of as a right regular prism with an infinite number of sides.
(C) 2011 Copyright Math Open Reference. All rights reserved