$\cos\left(\cos\left(-\frac{4}{5}\right)+\sin\left(\frac{2}{5}\right)\right)$

$\lim_{x\to\infty}\left(\frac{e^{x^2}-e^9}{x-3}\right)$

$\frac{dy}{dx}=\frac{5x^2}{4y}\:$

$\frac{u^2-3u}{7}=0$

$\frac{d}{dx}\left(arc\:cos\left(\sqrt{1-x}\right)\right)$

$\left(-18\right).\left(12\right):\left(4\right).\left(5\right):\left(10\right)$

$\lim\:_{x\to\:\infty\:}\left(\ln\:\left(e^x+1\right)\right)-\lim_{x\to0}\left(\ln\left(e^x+1\right)\right)$