$cos\left(x+y\right)$

$\frac{sec\left(x\right)}{1+sec\left(x\right)}-\frac{sec\left(x\right)}{1-sec\left(x\right)}=2\cdot csc^{2\:}\left(x\right)$

$12+9x-6x-19$

$\left(y^2-3xy-2x^2\right)dx+\left(xy-x^2\right)dy=0$

$\left|x\right|^2-3\left|x\right|=0$

$\frac{dy}{dx}=-3x^2y+2xe^{-x^3}$

$\int4x\left(x^2-10\right)^8dx$