$\int\frac{4\tan^{-1}\left(x\right)}{x^2+1}dx$

$\lim_{x\to1}\left(\sen\left(\frac{\pi}{x^{2}-1}\right)\right)$

$2b\:-\:5\:+\:6\:+\:9b$

$-\left(7-6+8-12+3-4\right)$

$\int\frac{\left(x+4\right)}{3x^2+9x+12}dx$

$\left(x-70\right)^3$

$\lim_{x\to0}\left(\frac{5}{x}-\frac{5}{x^2+x}\right)$