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

$\left(\frac{1}{4y^2}\:-\frac{1}{2}\right)\left(\frac{1}{4y^2\:}\:+\frac{1}{2}\right)$

$\int\frac{7lnx}{x}dx$

$\left(2x^2y\right)^2+6x^2y^3\cdot\frac{3x^2}{y}$

$5x^2\le x+10$

$\sqrt{4^2}+\:5^2$

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