Câu hỏi 45

\(I\left( 4 \right) = Q'\left( 4 \right) = \mathop {\lim }\limits_{t \to 4} \frac{{Q\left( t \right) - Q\left( 4 \right)}}{{t - 4}}\).

       \( = \mathop {\lim }\limits_{t \to 4} \frac{{2{t^2} + t - 36}}{{t - 4}} = \mathop {\lim }\limits_{t \to 4} \frac{{\left( {t - 4} \right)\left( {2t + 9} \right)}}{{t - 4}} = \mathop {\lim }\limits_{t \to 4} \left( {2t + 9} \right) = 17\,\,\left( A \right)\).

Chọn C.