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

$\lim_{x\to0}\left(\frac{1}{\left(tan\:2x\right)\left(ln\:1\right)}\right)$

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

$\frac{d}{dx}\left(x\left(x-4\sqrt{x}\right)\right)$

$5c+16.5=13.5+10c$

$\frac{x^5+x^2-3}{x^2-x+1}$

$x^4+y^9=\:46$