$\lim_{x\to\infty}\left(\frac{\sqrt{x^2+4x}}{x}\right)$

$\left(xy^2\right)\left(xy^2\right)^{-1}$

$\frac{dy}{dx}=0.03y\sqrt{x}$

$2^3b^2-2a^3b$

$\lim_{x\to0}\left(\frac{3x+1}{x}\right)$

$\lim_{x\to0}\left(\frac{e^x-x}{2e^x-x^2-2}\right)$

$\lim_{x\to\infty}\left(-\frac{\pi^{x-1}}{4\cdot12^{x-1}}\right)$