Basic Technical Mathematics, 11th Edition

21.10 Polar Coordinates

• Pole • Polar Axis • Polar Coordinates • Converting Between Polar and Rectangular Coordinates

To this point, we have graphed all curves in the rectangular coordinate system. However, for certain types of curves, other coordinate systems are better adapted. We discuss one of these systems here.

The Swiss mathematician Jakob Bernoulli (1654–1705) was among the first to make significant use of polar coordinates.

Instead of designating a point by its x- and y-coordinates, we can specify its location by its radius vector and the angle the radius vector makes with the x-axis. Thus, the r and $\theta$ that are used in the definitions of the trigonometric functions can also be used as the coordinates of points in the plane. The ...