二、決定研究主題，是研究設計的首要步驟。請問，於執行質化研究的過程中，如何選擇研究主題？並請輔以實例說明之。(30%)

1. (10%) Let f(x) be a differentiable function as shown in Figure 1. It needs to compute the integral $\int_{a}^{b} f(x)dx$. For some reason, the integration is not possible. We decide to linearize f(x) at x = a$ and use the trapezoidal area $A$ to approximate the integral, i.e. $ \int_{a}^{b} f(x) dx \approx A $. Please find the area A.