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