Question: Mark $(\sqrt{)}$ against the correct answer in each of the following:
$\int \frac{d x}{\left(4+9 x^{2}\right)}=?$
A. $\frac{2}{3} \tan ^{-1} \frac{3 x}{2}+C$
B. $\frac{1}{6} \tan ^{-1} 3 x+C$
C. $\frac{1}{6} \tan ^{-1} \frac{3 x}{2}+C$
D. none of these
Solution:
