$\lim_{x\to\infty}\left(\frac{x^8}{2^x}\right)$

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

$\frac{d}{dx}\left(\frac{2x}{y}\right)-5x^4-600=5y$

$\left(3+4y\right)\left(3-4y\right)$

$\left(10-\frac{40}{x^2}\right)\cdot\cos\left(y\right)$

$x+27=-9$

$\int_0^4-\sqrt{16-\left(x-4\right)^2}dx$