1.
Let f:[−1,3]→Rf: [-1, 3] \to \mathbb{R} be defined as

f(x)={∣x∣+[x],−1≤x<1x+∣x∣,1≤x<2x+[x],2≤x≤3f(x) = \begin{cases} |x| + [x], & -1 \le x < 1 \\ x + |x|, & 1 \le x < 2 \\ x + [x], & 2 \le x \le 3 \end{cases}


where [t][t] denotes the greatest integer less than or equal to tt. Then ff is discontinuous at: