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Câu hỏi: Cho biết $\int\limits_{0}^{3}{f\left( x \right)}\text{d}x=3, \int\limits_{0}^{5}{f\left( t \right)}\text{d}t=10$. Tính $\int\limits_{3}^{5}{2f\left( z \right)}\text{d}z$.
A. $\int\limits_{3}^{5}{2f\left( z \right)}\text{d}z=-7$.
B. $\int\limits_{3}^{5}{2f\left( z \right)}\text{d}z=14$.
C. $\int\limits_{3}^{5}{2f\left( z \right)}\text{d}z=13$.
D. $\int\limits_{3}^{5}{2f\left( z \right)}\text{d}z=7$.
A. $\int\limits_{3}^{5}{2f\left( z \right)}\text{d}z=-7$.
B. $\int\limits_{3}^{5}{2f\left( z \right)}\text{d}z=14$.
C. $\int\limits_{3}^{5}{2f\left( z \right)}\text{d}z=13$.
D. $\int\limits_{3}^{5}{2f\left( z \right)}\text{d}z=7$.
Ta có: $\int\limits_{3}^{5}{2f\left( z \right)}\text{d}z=2\int\limits_{3}^{5}{f\left( z \right)}\text{d}z=2\left[ \int\limits_{0}^{5}{f\left( z \right)}\text{d}z-\int\limits_{0}^{3}{f\left( z \right)}\text{d}z \right]=2\left( 10-3 \right)=14$.
Đáp án B.