$\frac{x\cos\left(x\right)\cdot\sec\left(x\right)}{\sin\left(x\right)+\sec\left(x\right)\cdot\cos\left(x\right)}$

$3m^3n-6mn^2+9m^3n^2$

$\frac{2}{3}+\frac{10}{x}$

$20x^3y+40x^2y^2-60xy^3$

$\int\frac{2x}{\left(1+x\right)}dx$

$\:x\left(x\:-\:y\right)\:+\:2xy$

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