1.
Let a function f:R→Rf: \mathbb{R} \to \mathbb{R} be defined as
f(x)={sin⁡x−ex,x≤0a+[−x],0<x<12x−b,x≥1f(x) = \begin{cases} \sin x - e^x, & x \le 0 \\ a + [-x], & 0 < x < 1 \\ 2x - b, & x \ge 1 \end{cases}

where [x][x] is the greatest integer less than or equal to xx. If ff is continuous on R\mathbb{R}, then (a+b)(a + b) is equal to: