$\left(x^{3a}+20\right)\left(x^{3a}-20\right)$

$\frac{d}{dx}\left(\frac{y^2}{1+x^2}=c\right)$

$\lim_{x\to\infty}\left(\sqrt{x^2+5}-\left(x+2\right)\right)$

$\lim_{x\to-\infty}\left(\frac{\sqrt{4x^2+1}}{1-x}\right)$

$x^2-x-12\ge0$

$\int\left(1-\sin2x\right)^2dx$

$\cos^2x-\sec^2z$