$\frac{dy}{dx}=\sec\left(x\right)^2\sec\left(x\right)^3$

$1x+\frac{1}{2}$

$\frac{cos\left(x\right)+1}{\cos\left(x\right)-1}=\frac{1+sec\left(x\right)}{1-sec\left(x\right)}$

$\lim_{x\to1}\left(\frac{9sin\left(9\pi x\right)}{cos\left(\pi x\right)+x}\right)$

$\frac{8a^2+12ab}{8a^2}$

$x=-11y-140\:$