$2x^25x^2+5x-2$

$\int\frac{5x-10}{\left(x^2-4x+11\right)^4}dx$

$\left(\frac{1}{n+1}\right)^2$

$\sec^2\left(a\right)\left(\cot^2\left(a\right)+1\right)$

$\frac{-2xy^2}{2x^2y}$

$\left(x^2+2x-8\right)\left(x-3\right)$

$\lim_{x\to+\infty}\left(\frac{e^x-2}{e^x-1}\right)$