Polar and rectangular coordinates.

Description
The are of a pie in a circle of radius r is calculated in polar coordinates. Also area of a variable pie is derived by using the Riemann sum. Application of polar coordinates is explained through some practical examples. Rectangular equations are explained in this video.
Prof. David Jerison, Single Variable Calculus : 30. Exam 4 Review, Massachusetts Institute of Technology: MIT OpenCourseWare),http://ocw.mit.edu (Accessed July 26,2011). License: Creative Commons BY-NC-SA:http://ocw.mit.edu/terms/#cc