ข้อสอบคณิต 2 - ธันวาคม 2559

$$\begin{gathered} \mathrm{จากโจทย์} \\ f\left(x\right) = \left|\left|x-3\right|-3\right| \\ \mathrm{แทน} x = 4 \\ \mathrm{จะได้} f\left(4\right) = \left|\left|4-3\right|-3\right| \\ = \left|\left|1\right|-3\right| \\ = \left|1-3\right| = \left|-2\right| \\ = 2 \end{gathered}$$

$$\begin{gathered} \mathrm{แทน} x = -4 \\ \mathrm{จะได้} f(-4) = |\left|-4-3\right|-3| \\ = |\left|-7\right|-3| \\ = |7-3| = \left|4\right| \\ = 4 \end{gathered}$$

$$\begin{gathered} \mathrm{ดังนั้น} \frac{f\left(4\right)-f\left(-4\right)}{2} = \frac{2-4}{2} = -1 \\ \mathrm{ตอบ} 2 \end{gathered}$$