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

$\lim_{x\to0}\left(\sin\left(\pi\sec\left(x\right)\right)\right)$

$7z^2+7$

$\lim_{x\to0}\left(\frac{sen\left(4x\right).sen\:5x}{\left(x-x^2\right)^2}\right)$

$\left(\frac{6x^{-8}\cdot y^{-3}}{18x^4y^{-5}}\right)^{-1}$

$\int x\sqrt{x}^2-4dx$

$\int e^{-0.02t}\left(e^{-0.13t}+4\right)dt$