$3x^2-2x+6$

$\lim_{x\to0}\left(\frac{sen\:x}{x^2}\right)$

$30\cdot10-180+60+13$

$\int_0^{\frac{1}{2}}\:\frac{cos\theta\:\cdot\:\:cot\theta\:\cdot\:\:d\theta\:}{sin\theta\:}$

$\left(t-2x\right)\left(r-2x\right)$

$\lim_{x\to\infty}\left(\left(5x\right)e^{-x}\right)$

$\lim_{x\to-\infty}\left(\frac{3x+2}{\sqrt{5x^2-5}}\right)$