$6\left(2r\right)$

$\lim_{x\to1}\left(\frac{\pi}{x-1}-\frac{1}{\ln\left(x\right)}\right)$

$\frac{dy}{dx}\left(xy=sin\left(xy+x\right)\right)$

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

$\int\left(e^x-\frac{2}{x}+\frac{1}{x^2}\right)dx$

$cos12x=0.5$

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