$\lim_{x\to-5}\left(\frac{x^2+7x+10}{x^2+13x+40}\right)$

$\frac{6x+8}{1-x}$

$\frac{a^2b}{5}-\frac{6a^2b}{5}\:-3$

$\lim_{x\to\infty}\left(\cos\left(x\left(\pi\right)\right)\right)$

$cos2x-1=0$

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

$\int\cos^3\left(3x\right)\sin^2\left(3x\right)dx$