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