$\left(3-x^4\right)^2$

$\lim_{x\to\infty}\left(\frac{2e^{2x}-2}{x^2+x}\right)$

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

$2x\left(-10x^3y\right)$

$\int\frac{x-1}{x^4-1}dx$

$\frac{tan^3x}{\sqrt{sec\:x}}$

$\int\frac{x-1}{\left(x^2+x\right)}dx$