$\lim_{x\to\frac{\pi}{2}}\left(\frac{2}{cos^2x}-\frac{1}{1-sen\:x}\right)$

$\frac{28a^2b^3c}{7a^2b}$

$729a^3-1000$

$2\left(-2-4n\right)+2\left(-2n-1\right)$

$\:\frac{d}{dx}\left(\frac{\left(x+3\right)^6\left(x-1\right)^3}{\left(x+2\right)^3}\right)$

$13.16-2.25$

$\frac{4^{2x+1}}{16^{7-x}}=4^{x+2}$