Let \( f(x)=\ (x)^2-[ x+3] - 3,\ x\in \mathbb{R} \), where \([ . ]\) is the greatest integer function. Then
\( f(x)<0 \) only for \( x\in [-1,3) \)
\( \displaystyle \int_{0}^{2}f(x)\,dx=-6 \)
\( f(x)=0 \) for finitely many values of \( x \)
\( f(x)>0 \) only for \( x\in [4,\infty) \)