$\frac{\left(\sec\:\:\left(x\right)-\tan\:\:\left(x\right)\right)^2+1}{\csc\left(x\right)\left(\sec\left(x\right)-\tan\left(x\right)\right)}=2\tan\left(x\right)$

$a^2-8a-20$

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

$8\:-\:12\:-\left(6\:+\:4\right)$

$3\left(\frac{1}{2}m\right)^2\left(\frac{3}{5}n\right)$

$\left(-8x^2y\right)\:\left(-4x+9y\right)$

$\int x^4\sqrt{8-x}dx$