To find the area of the shaded region between the circle and the square, we need to subtract the area of the circle from the area of the square:
- Area of the square: \( A_{\text{square}} = f(r) = 4r^2 \)
- Area of the circle: \( A_{\text{circle}} = g(r) = \pi r^2 \)
The area of the shaded region, \( A_{\text{shaded}} \), can be represented by the function:
\[ A_{\text{shaded}}(r) = A_{\text{square}} - A_{\text{circle}} = 4r^2 - \pi r^2 = (4 - \pi)r^2 \]
Next, let's determine the domain of this function. Since radius \( r \) cannot be negative, the domain is:
\[ r \geq 0 \]
So the correct response is:
The function \( (f-g)(r)=(4-\pi)r^2 \) represents the area of the shaded region. The domain is \( r \geq 0 \).