3. The function \( f \) is defined on the closed interval \( [-2,8] \) and satisfies \( f(2)=1 \). The graph of \( f^{\prime} \), the derivative of \( f \), consists of two line segments and a semicricle, as shown in the figure below.
(a) Does \( f \) have a relative minimum, a relative maximum, or neither at \( x=6 \) ? Give a reason for your answer.