$\lim_{x\to0}\left(x\cdot\:sen\left(\frac{3}{x}\right)\right)\:$

$7k-4m;\:m=-5\:;\:k=4$

$\frac{sec^2x\left(tan^2x\right)}{cotx\left(cscx\right)}$

$\frac{m+6}{18}+\frac{2}{9}$

$y-7<-12$

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

$\frac{dy}{dx}=\frac{1}{3}x-3y$