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Câu hỏi: Tích phân $\int_{-1}^{3}{\left( 3{{x}^{2}}-1 \right)}~\text{d}x$ bằng
A. $8$.
B. $\dfrac{26}{3}$.
C. $24$.
D. $26$.
A. $8$.
B. $\dfrac{26}{3}$.
C. $24$.
D. $26$.
Ta có $\int_{-1}^{3}{\left( 3{{x}^{2}}-1 \right)}~\text{d}x=\left. \left( {{x}^{3}}-x \right) \right|_{-1}^{3}=\left( {{3}^{3}}-3 \right)-\left[ {{\left( -1 \right)}^{3}}-\left( -1 \right) \right]=24.$
Đáp án C.