For a given density function f(x,y)=1, the total mass M in R is given by
M=∬{R} f(x,y)dxdy and the center of gravity of mass in R has the coordinates x ̅ , y ̅
, where x ̅ =(1/M)∬{R} xf(x,y)dxdy , y ̅ = (1/M)∬{R} yf(x,y)dxdy.
If R is the region between the circles x^2+y^2 = 1 and x^2+y^2=9
in the first quadrant, find M and x Ì….