$\lim_{x\to\infty}\sqrt{\frac{x^2+x+3}{\left(x-1\right)\left(x+1\right)}}$

$\frac{d}{dx}\frac{f^3}{1+f^2}$

$\int\sec^2\left(\frac{2x^2}{5}\right)xdx$

$\lim_{x\to\infty}\left(-\pi^{x-1}\right)$

$\frac{512m^9-19683n^9}{2m-3n}$

$x^2=8-2x$

$\int_0^{sen\left(x+\pi\right)}\left(e^{-t^2}\right)dt$