Example 1: Circular Cylinder

Sketch the portion of the cylinder x² + y² = 1 where 1 ≤ z ≤ 2 (Figure 11.1.12).

	Draw the curve x2 + y2 = 1 in the (x, y) plane. The curve is a circle of radius one.
	Draw the three coordinate axes and the horizontal planes z = 1, z = 2.
	Draw the circles x2 + y2 = 1 where the surface intersects the two planes z = 1,z = 2.
Figure 11.1.12	Complete the sketch by drawing heavy lines for all edges which would be visible on an "opaque" model of the given surface. This surface is called a circular cylinder.