Find the limit of $\frac{2x+1}{4x^2}$ as $x$ approaches $\infty $

Find the limit

$\lim_{x\to\infty}\left(\frac{7x^2}{x-x^3}\right)$

Find the limit

$\lim_{x\to\infty}\left(\frac{x+x^2}{1-2x^2}\right)$

Find the limit

$\lim_{y\to\infty}\left(\frac{2y^2-3y+5}{y^2-5y+2}\right)$

Find the limit

$\lim_{x\to\infty}\left(\frac{x+2}{x-1}\right)^x$

Find the limit

$\lim_{x\to\infty}\left(\frac{x}{x^2+1}\right)$

Find the limit

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

Find the limit

$\lim_{x\to0}\left(\frac{x^2}{1-cos\left(x\right)}\right)$