Ответ (Неопределённый)
[src] / /x\
| x*tan|-|
| x / 2/x\\ \2/ x / /x\\
| ------- dx = C - log|1 + tan |-|| + -------- - -------- + log|tan|-||
| 2 \ \2// 2 /x\ \ \2//
| sin (x) 2*tan|-|
| \2/
/
$$\int \frac{x}{\sin^{2}{\left(x \right)}}\, dx = C + \frac{x \tan{\left(\frac{x}{2} \right)}}{2} - \frac{x}{2 \tan{\left(\frac{x}{2} \right)}} - \log{\left(\tan^{2}{\left(\frac{x}{2} \right)} + 1 \right)} + \log{\left(\tan{\left(\frac{x}{2} \right)} \right)}$$