$\lim_{x\to-0.001}\left(\frac{sen2x}{x}\right)$

$\lim_{x\to\infty}\left(\frac{x^a}{e^x}\right)$

$\frac{6x-2}{3}>-3$

$\frac{3}{a+2}+\frac{8}{a-5}$

$\lim_{x\to0}\left(2^{-\frac{1}{n}}\right)$

$\left(+100\right)\:\cdot\:\left(-10\right)\:\cdot\:\left(+1\right)\::\:\left(-1\right)\:$

$\left[\left(a+b\right)+\left(x+y\right)\right]\left[\left(a+b\right)-\left(x-y\right)\right]$