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