\(\int\limits^2_1\dfrac{\text{d}x}{2x+3}\) bằng
\(2\ln\dfrac{7}{5}\).\(\dfrac{1}{2}\ln35\).\(\ln\dfrac{7}{5}\).\(\dfrac{1}{2}\ln\dfrac{7}{5}\).Hướng dẫn giải:\(\int\frac{\text{d}x}{2x+3}=\frac{1}{2}\int\frac{\text{d}\left(2x+3\right)}{2x+3}=\frac{1}{2}\ln\left|2x+3\right|+C\). Do đó \(\int\limits^2_1\frac{\text{d}x}{2x+3}=\frac{1}{2}\left(\ln7-\ln5\right)=\frac{1}{2}\ln\frac{7}{5}\).