Quadric Cylinders

If z does not appear in an equation, its graph will be a cylinder parallel to the z-axis. The cylinder is generated by a line parallel to the z-axis moving along a curve in the plane z = 0.

The graph (in space) of is an elliptic cylinder.It intersects any horizontal plane z = z₀ in an ellipse.

The graph of is a parabolic cylinder.

The graph of is a hyperbolic cylinder.

Cylinders parallel to other axes are similar. The three types of quadric cylinders are shown in Figure 11.1.4.

Figure 11.1.4