Integral Calculus
86489
\(\int_2^3 \frac{d x}{x^2+x}=\)
1 \(\log \left(\frac{3}{2}\right)\)
2 \(\log \left(\frac{8}{9}\right)\)
3 \(\log \left(\frac{3}{4}\right)\)
4 \(\log \left(\frac{9}{8}\right)\)
Explanation:
(D) :
\(\mathrm{I}=\int_2^3 \frac{\mathrm{dx}}{\mathrm{x}^2+\mathrm{x}}\)
\(=\int_2^3 \frac{d x}{x(x+1)} d t=\int_2^3 \frac{(x+1)-x}{x(x+1)} d x\)
\(\int_2^3\left[\frac{(x+1)}{x(x+1)}-\frac{x}{x(x+1)}\right]\)
\(=\int_2^3\left[\frac{1}{x}-\frac{1}{x+1}\right] d x=[\log x]_2^3-[\log (1+x)]_2^3\)
\(=\left[\log \left(\frac{x}{x+1}\right)\right]_2^3=\log \left(\frac{3}{4}\right)-\log \left(\frac{2}{3}\right)\)
\(=\log \frac{3}{4} \times \frac{3}{2}=\log \frac{9}{8}\)