$\lim_{x\to3}\left(2x-1\right)$

$\frac{\cot\left(x\right)}{\sin\left(2x\right)}=\frac{1}{2\sin^2\left(x\right)}$

$\frac{x^4+x^2-3}{x^3}$

$2\sqrt{5}+7\sqrt{5}-4\sqrt{5}$

$\frac{d}{dx}\left(\frac{3x}{y}-8x^3-6=3y\right)$

$\frac{dy}{dx}-4y=xy^{\frac{3}{2}}$

$\left(1+b\right)^5$