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)