$\lim_{x\to1}\left(\frac{\cot\left(\frac{\pi}{2}\right)\left(x\right)}{1-x}\right)$

$\left(-5\right)+\left(+2\right)-\left(-1\right)+\left(+4\right)-\left(+6\right)$

$\int\tan\left(2\right)x\:dx$

$\frac{dy}{dx}=\left(3x^4\right)$

$\frac{d^2y}{dx^2}\left(-\frac{1}{4}x^{-4}-\frac{1}{16}+\frac{1}{4}x^4\right)$

$\lim_{x\to9}\left(\frac{2x^2+17x-9}{x^2-81}\right)$

$\left(-84\right)\left(+65\right)$