x2+(y-1)2=1→r=2sin6 (x-1)2+y2=1→r=2cos0 π/4P2sin rcos.rsinorar r/2 er2 cos e 兀/4J0 f(rose, rsinerdr(1,1) ( 1) 1 2sin 2 2 x + y − =  r = ( 1) 1 2cos 2 2 x − + y =  r =     =    2sin 0 / 4 0 I d f (r cos ,rsin )rdr      +    2cos 0 / 2 / 4 d f (r cos ,rsin )rdr