$2\int\frac{e^{-2x}}{e^{-x}+1}dx$

$\frac{x^2+2x-15}{x-1}$

$cos\left[\frac{\left(\frac{3\pi}{5}\right)}{2}\right]-cos\left[\frac{\left(\frac{\pi}{5}\right)}{2}\right]$

$\int\left(x^2+2\right)\left(x+3\right)dx$

$-x^3+x+\frac{1}{x}$

$y^2-y-6$

$\left(4x+2\right).\left(4x+4\right)$