$\frac{1}{\cos\left(x\right)}-\sin\left(x\right).$

$\lim_{t\to0}\left(\frac{8t}{\sqrt{2t+81}-9}\right)$

$\int\frac{y}{\left(y^2+16\right)}dx$

$x^2+0.2x-0.00000175$

$\int\frac{3}{\left(x+1\right)^2}dx$

$\frac{7x^5-22+3x^3-2}{-x+2}$

$\lim_{x\to16}\left(\frac{x-4}{\sqrt{x}-4}\right)$