$7y^5+\frac{7}{4}xyz-\frac{6}{3}xyz+\frac{2}{3}xz+\frac{6}{4}xyz-xz$

$\frac{d}{dx}\left(\sqrt{x+s}=\frac{5}{x}+\frac{3}{s}\right)$

$\left(\tan^2x+1\right)\left(\cos^2x+1\right)-\tan^2x$

$\lim_{x\to0}\left(\frac{ln\left(1+x^2\right)}{x^2}\right)$

$-\left(-12\right)-\left(12+7\right)$

$\frac{xdy}{ydx}=\frac{\sqrt{1+y^2}}{\sqrt{1+x^2}}$

$\lim_{x\to1}\left(\frac{\sqrt{1-x^2}}{\sqrt{1-x^3}}\right)$