$\frac{d^2}{dx^2}\left(sen\left(x\right)\right)$

$x+1=\frac{4}{x+1}$

$\frac{m^2n+2n}{6m}$

$\left(\frac{\left(2m^{\frac{1}{3}}n^{\frac{5}{6}}\right)^6}{\left(2m^{-2}n^6\right)^{-1}\left(2-n\right)^5}\right)$

$\sqrt{27a}$

$\frac{12-x}{x}=\frac{5}{7}$

$105-78-\left(-13\right)$