7. Polar Coordinates
For certain functions, rectangular coordinates (those using x-axis and y-axis) are very inconvenient. In rectangular coordinates, we describe points as being a certain distance along the x-axis and a certain distance along the y-axis.
polar coordinates
But certain functions are very complicated if we use the rectangular coordinate system. Such functions may be much simpler in the polar coordinate system, which allows us to describe and graph certain functions in a very convenient way.
Polar coordinates work in much the same way that we have seen in trignometry(radians and arc length, where we used r and θ) and in the polar form of complex numbers (where we also saw r and θ).