Cho hàm số\(y = \,\left\{ \begin{array}{l}\frac{2}{{x - 1}},\,\,\,x \in \left( { - \infty ;\,\,0} \right)\\\sqrt {x + 1} ,\,\,\,\,x \in \left[ {0;\,\,2} \right]\\{x^2} - 1,\,\,\,x...

Câu hỏi :

Cho hàm số\(y = \,\left\{ \begin{array}{l}\frac{2}{{x - 1}},\,\,\,x \in \left( { - \infty ;\,\,0} \right)\\\sqrt {x + 1} ,\,\,\,\,x \in \left[ {0;\,\,2} \right]\\{x^2} - 1,\,\,\,x \in \left( {2;\,\,5} \right]\end{array} \right..\,\,\)  Tính \(f(4),\) ta được kết quả :