Cho hàm số  \(f(x) = \left\{ \begin{array}{l} - 2(x - 2){\rm{ }}\,\,\,\,\,,{\rm{  - 1}} \le {\rm{x}}...

Câu hỏi :

Cho hàm số  \(f(x) = \left\{ \begin{array}{l}
 - 2(x - 2){\rm{ }}\,\,\,\,\,,{\rm{  - 1}} \le {\rm{x}} < {\rm{1 }}\\
\sqrt {{x^2} - 1} \,\,\,\,\,\,\,\,\,\,\,\,\,,{\rm{ x}} \ge {\rm{1}}
\end{array} \right.\)Tính f(-1)