$\lim_{x\to0}\left(\frac{e^x-\left(1-12x\right)}{x}\right)$

$\frac{csc^4\theta\:-1}{cot^2\theta\:}=2+cot^2\theta\:$

$\int6x\sec^2\frac{x^2}{3}dx$

$\int_{0}^{2}z^{3}\sqrt{z^{2}+4}dz$

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

$-3+7+1-4+5-12+9$

$f\left(x\right)=\left(x^2-x+2\right)\cdot e^{-x}$