$\lim_{x\to\infty}\left(\frac{\sin\left(\frac{3}{x}\right)}{\left(1-\cos\left(\frac{2}{x}\right)\cdot x^2\cdot\sin\left(\frac{1}{x}\right)\right)}\right)$

$\frac{1}{\sqrt{sec^2x}}$

$\frac{2x^5y^4}{8y^5}$

$5+\left|-18+11\right|+\left(7+-15\right)-10$

$\frac{3x^4-2x^3-6x^2+3x-2}{x^2+x-2\:}$

$10xy-5z-9xy+4z+z$

$\left(3x^6-4x\right)^2$