$-csc\frac{x}{2}.cotg\frac{x}{2\:}$

$a^2b^9\left(a^4b^3c\right)$

$\frac{x^2-3x^2-2}{x^2+1}$

$2px+p^2=y^2$

$\left[3\cdot2^5+13\cdot\left(-2\right)\right]+7\left[8-\left(4-9\right)\right]$

$\int^20\left(x^2-x\right)dx$

$\lim_{n\to\infty}\frac{\left(\sqrt{10n^2+7n+3}\right)}{n^2}$