$cot\:\left(y\right)\:dy\:=\:\frac{1}{-\left(1-x^2\right)}dx$

$15\cdot15^2$

$\int\left(\pi^2-x^2\right)\cdot\sin\left(nx\right)dx$

$x^2-60x+900$

$\lim_{x\to\infty}\left(\frac{4+x-2x^3}{2x^2-3x+11}\right)$

$\frac{2}{n^2}-\frac{n-5}{n^2}=\frac{3n+15}{n^2}$

$\int\frac{sin\left(ln\left(25x\right)\right)}{x}dx$