Question
Find the area of the region enclosed between the two circles x2 + y2 = 1 and (x - 1)2 + y2 = 1.
Solution
The equation of two circles are
...(1)
and 
...(2)
Centre of circle (1) is O (0, 0) and radius OA = 1
Centre of circle (2) is A (1, 0) and radius AO = 1
Subtracting (1) from (2), we get,
Putting 
in (1), we get,
points of intersection of circles (1) and (2) are
Required area = Area of region OQAP
= 2 (area of region OMAP)
= 2 (area of region OMPO + area of region MAPM)
