$x^4-\left(x+4\right)\left(x-4\right)\left(x^2+19\right)$

$y\frac{dy}{dx}=\cos\left(x\right)$

$\frac{8+x^2}{2-x}$

$\left(3x^2-4x^{-3}+\frac{2}{x}\right)\left(3x+2x^3-2\right)$

$a+a-6a$

$\left(6^{n+2}\:+\:4b^{m-1}\right)\:\left(6a^{n+2}\:-\:4b^{m-1}\right)$

$\int cot\left(2x^4+16\right)x^3dx$