$\lim_{x\to0}\left(\frac{\sqrt{9x+1}}{\sqrt{x+1}}\right)$

$\lim_{x\to0}\left(\frac{\sqrt{25-x^2}}{x-5}\right)$

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

$-2cos\left(x\right)=\frac{sin\left(x\right)}{sin^2\left(x\right)}$

$\frac{x^4-x^3-2x}{x+3}$

$\frac{dy}{dx}=2x^2+5$

$3-\left[2-\left(1-3\right)+4\right]-8$