$\lim_{x\to0}\left(\frac{1-5x}{3x+1}\right)^{\frac{\tan\left(x^2\right)}{x^3}}$

$f'\left(x\right)=\left(5x\right)^{ln\:5x}$

$\left(x^4\right)\cdot\left(x^2-x^6+2x^3-1\right)$

$2x^3-x^{3\:}-x^3$

$\frac{dy}{dx}9\frac{2}{x+1}$

$z^2+z+0$

$-2\left(\ln e^4\right)^2-e^{2\ln3}$