Question:
Mark $(\sqrt{)}$ against the correct answer in each of the following:
$\int \operatorname{cosec}^{3}(2 x+1) \cot (2 x+1) d x=?$
A. $\frac{1}{4} \operatorname{cosec}^{4}(2 x+1)+C$
B. $-\frac{1}{3} \operatorname{cosec}^{3}(2 \mathrm{x}+1)+\mathrm{C}$
C. $-\frac{1}{6} \operatorname{cosec}^{3}(2 \mathrm{x}+1)+\mathrm{C}$
D. $\frac{1}{2} \operatorname{cosec}(2 x+1) \cot (2 x+1)+C$
Solution:
