Lecture 21 : Area between two curves [Section 21.2]
Since
the required area is
(ii)
Area of a sector:
Compute the area A of the sector of a circle of radius marked by the points where is fixed. This area can be regarded as the area of the region bounded by the curves
Hence
marked by the points 
where 
is fixed. This area can be regarded as the area of the region bounded by the curves 
