$\left(x+y+2z^2\right)+\left(-x+y+z^2\right)$

$\frac{d}{dx}\left(x^3+y^3=3x^2y-3xy^2\right)$

$\int45csc\left(9x\right)cot\left(9x\right)dx$

$\frac{e^{-1^2}}{2}$

$\frac{sen.sec}{cotg}$

$\lim_{x\to0}\left(\frac{e^x-\cos\left(x\right)-\sin\left(x\right)}{x\sin\left(x\right)}\right)$

$\int\frac{5x^2-3x+1}{\left(x^2+1\right)\left(x-2\right)}dx$