$\lim_{x\to0}\left(\frac{x}{4+\sin\left(x\right)}\right)$

$\int\frac{cos\:2x}{cosx-senx}dx$

$x^2\ln\left(x\right)dx=\frac{\left(y+1\right)^2}{y}dy$

$\frac{d}{dx}\log e\left(x\right)$

$\sqrt{7}\cdot4\sqrt{3}$

$x\frac{dy}{dx}=2y+x^3\sin\left(x\right)$

$\frac{40}{x}+\frac{x}{10}=\frac{x}{5}$