Câu 19 Mã đề 103 Thi THPTQG 2018
\(\int\limits^2_1\frac{\text{d}x}{3x-2}\) bằng
\(2\ln2\). \(\frac{1}{3}\ln2\). \(\ln2\). \(\frac{2}{3}\ln2\). Hướng dẫn giải:\(\int\frac{\text{d}x}{3x-2}=\frac{1}{3}\int\frac{\text{d}\left(3x-2\right)}{3x-2}=\frac{1}{3}\ln\left|3x-2\right|+C\). Do đó \(\int\limits^2_1\frac{\text{d}x}{3x-2}=\frac{1}{3}\left(\ln4-\ln1\right)=\frac{2}{3}\ln2\)