$\frac{\sin\beta}{1-\cos\beta}+\frac{1-\cos\beta}{\sin\beta}=2\csc\beta$

$\lim_{x\to\infty}\left(xsin\left(\frac{4}{x}\right)\right)$

$3\left(7b\right)$

$\frac{437}{-19}$

$a^2b^2+a^3b^3-ab$

$\frac{\left(3a^{-1}b^2\right)^{-2}}{\left(2a^2b^{-1}\right)^{-3}}$

$10\:-\:x\:\:<\:\:-\:5\:+\:2x\:$