Module 7 : Applications of Integration - I
Lecture 21 : Area between two curves [Section 21.2]
 

By symmetry, this formula also holds when . In particular, the area of a disc of radius is

 
21.2.6 Area in polar coordinates:
  Consider a curve . Let us find the area of the sector bounded by this curve and the rays
 
 

In view of the formula in example above, we can define

provided the function is Riemann integrable.

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