$6x^2-2x^2+6x^2-2x-4x^3-2x^2-2x$

$\lim_{x\to3}8$

$\:\:\int\frac{cot\:t}{1+sen\:t\:}\:dt$

$6x^2y+7xy$

$\sqrt{52}\cdot\sqrt{52}$

$\lim_{x\to\infty}\left(\sqrt{x^2-1}-\sqrt{x^2-3x}\right)$

$\frac{\tan^2\left(x\right)+\cot^2\left(x\right)+2}{\sec^2\left(x\right).\csc^2\left(x\right)}=1$