$12x\left(\left(2x^2+1\right)^2\right)\cdot\left(\frac{\left(x\right)}{\left(\left(x^2-1\right)\right)}\right)$

$\int-4e^{2x+3}dx$

$\frac{dy}{dx}=\frac{\sqrt{1-x^4}\left(x^2+1\right)}{x}$

$\lim_{x\to\infty}\frac{2x-1}{x^2+5}$

$y^3-4y^2+y+6$

$\frac{dy}{dx}=\frac{x-y+1}{x-y-1}$

$\int_{\frac{\pi}{2}}^{\pi}\left(\cos\left(nx\right)\right)dx$