$\lim_{x\to\infty}\left(e^{4x}-e^{-4x}\right)$

$\frac{dy}{dt}=4t-12ty-10t\cdot\sin\left(2t\right)$

$\int\csc^5\left(3+5x\right)dx$

$\lim_{x\to0}\left(\frac{1}{x-12}-\frac{1}{\sqrt{x-12}}\right)$

$\left(5x^{2}-21\left(5x^{2}+2\right)$

$\left(x^3-\frac{1}{4}x^{-3}\right)^2$

$\sqrt[2.1]{9}$