$\lim_{x\to\infty}\left(\frac{\ln\left(3x\right)}{x^3}\right)$

$tan^{-1}\left(tanx\right)=x$

$\frac{dy}{dx}-6x^5y=12x^3\cdot e^{x^6}$

$2x^2+11x-6$

$\frac{\sin\left(x\right)}{1+\sin\left(x\right)}-\frac{\sin\left(x\right)}{1-\sin\left(x\right)}$

$21x^4-4x^3\left(14x^5+13\right)$

$4x-2\ge6x-5$