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Câu hỏi: $\int\limits_{1}^{2}{\dfrac{\text{d}x}{2x+3}}$ bằng
A. $\dfrac{1}{2}\ln \dfrac{7}{5}$.
B. $2\ln \dfrac{7}{5}$.
C. $\dfrac{1}{2}\ln 35$.
D. $\ln \dfrac{7}{5}$.
A. $\dfrac{1}{2}\ln \dfrac{7}{5}$.
B. $2\ln \dfrac{7}{5}$.
C. $\dfrac{1}{2}\ln 35$.
D. $\ln \dfrac{7}{5}$.
$\int\limits_{1}^{2}{\dfrac{\text{d}x}{2x+3}}=\left. \left( \dfrac{1}{2}\ln \left| 2x+3 \right| \right) \right|_{1}^{2}=\dfrac{1}{2}\ln 7-\dfrac{1}{2}\ln 5=\dfrac{1}{2}\ln \dfrac{7}{5}$.
Đáp án A.