$\lim_{x\to0}\left(\frac{1-\cos\left(0\right)}{\sin\left(0\right)}\right)$

$x^2+13x+6$

$\left(1+\cot^2\left(y\right)\right)\left(\cos\left(2y\right)+1\right)$

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

$\frac{4\pi}{\pi}$

$\int_0^{\pi}\left(sen\left(2x\right)\right)dx$

$\left(n^3-n^2+2n-1\right)\cdot\left(-3n+1\right)$