$\lim_{w\to27}\left(\frac{\cos\left(wt\right)-\cos\left(27t\right)}{729-w^2}\right)$

$9a+\frac{7}{9}<0$

$\frac{dy}{dx}y=\left(2x+1\right)^2+2x+1$

$3412.2\cdot7$

$2d^2-8d$

$\frac{sin\left(x\right)}{cos\left(x\right)}\left(cot^2x\right)$

$\frac{d^{20}}{dx^{20}}\left(cos\left(2x\right)\right)$