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Câu hỏi: Nếu $\int\limits_{0}^{3}{f\left( x \right)\text{d}x=6}$ và $\int\limits_{0}^{2}{f\left( x \right)\text{d}x=4}$ thì ${\int\limits_{2}^{3}{f\left( x \right)\text{d}x}}$ bằng
A. $10$.
B. $2$.
C. $-10$.
D. $-2$.
A. $10$.
B. $2$.
C. $-10$.
D. $-2$.
Ta có: $\int\limits_{0}^{3}{f\left( x \right)\text{d}x=\int\limits_{0}^{2}{f\left( x \right)\text{d}x}+\int\limits_{2}^{3}{f\left( x \right)\text{d}x}}$.
Suy ra $\int\limits_{2}^{3}{f\left( x \right)\text{d}x}=\int\limits_{0}^{3}{f\left( x \right)\text{d}x-\int\limits_{0}^{2}{f\left( x \right)\text{d}x}}=6-4=2$.
Suy ra $\int\limits_{2}^{3}{f\left( x \right)\text{d}x}=\int\limits_{0}^{3}{f\left( x \right)\text{d}x-\int\limits_{0}^{2}{f\left( x \right)\text{d}x}}=6-4=2$.
Đáp án B.