$2\cdot3x$

$tanx\left(secx-1\right)\left(secx+1\right)$

$\sec^2\left(x-1\right)\cos^2\left(x\right)$

$\frac{\cot\left(1\right)}{\tan\left(1\right)}$

$\lim_{x\to-0.01}\left(\frac{sen2x}{x}\right)$

$x^3-2x^3$

$\frac{dy}{dx}=x\left(e^{-y}\right)\left(\ln\left(x\right)\right)$