讨论稿41题的图是不是这样的？（没人理我？）

sdcar2010

If so the shaded area is the half of the square.

sdcar2010

我算下来是a^2(1/2+π/8)。不过我很粗心，也可能算错。

-- by 会员 gwendolinecn (2010/12/28 23:20:00)

My reasoning is:
The shaded area = half circle + half square - 2* (a quarter of circle)

However, 2 quarters of a circle = half circle.

So the shaded area = half square.