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Câu hỏi: Nếu $\int\limits_{1}^{2}{f\left( x \right)\text{d}x}=5$ và $\int\limits_{1}^{3}{f\left( x \right)\text{d}x}=15$ thì ${\int\limits_{2}^{3}{f\left( x \right)\text{d}x}}$ bằng
A. $20$.
B. $25$.
C. $10$.
D. $3$.
A. $20$.
B. $25$.
C. $10$.
D. $3$.
$\int\limits_{1}^{3}{f\left( x \right)\text{d}x}=\int\limits_{1}^{2}{f\left( x \right)\text{d}x}+\int\limits_{2}^{3}{f\left( x \right)\text{d}x}\Rightarrow \int\limits_{2}^{3}{f\left( x \right)\text{d}x}=\int\limits_{1}^{3}{f\left( x \right)\text{d}x}-\int\limits_{1}^{2}{f\left( x \right)\text{d}x}=15-5=10$.
Đáp án C.