设圆2与圆1的半径分别为r,R
2R=2 R=1
(2-r)^2+1=(r+1)^2
4-4r+r^2+1=r^2+2r+1
6r=4
∴r=2/3
S阴=(1/4)S大圆-(1/2)*[S圆1+S圆2]
=4π/4-(1/2)*[π+(4/9)π]
=π-(13/18)π
=(5/18)π
设圆2与圆1的半径分别为r,R
2R=2 R=1
(2-r)^2+1=(r+1)^2
4-4r+r^2+1=r^2+2r+1
6r=4
∴r=2/3
S阴=(1/4)S大圆-(1/2)*[S圆1+S圆2]
=4π/4-(1/2)*[π+(4/9)π]
=π-(13/18)π
=(5/18)π