$\lim_{n\to\infty}\left(\left|\frac{\arctan\:\left(n+1\right)}{\arctan\:\left(n\right)}\right|\right)$

$\left(2xz^2\right)^2$

$\lim_{x\to\frac{-\pi}{4}}\left(\frac{\cos\left(2x\right)}{\cos\left(x\right)+\sin\left(x\right)}\right)$

$3x^2-24xy+48y^2$

$12+\left(-5\right)\cdot\left|8+\left(-9\right)\right|$

$\sqrt{2^2-x^2}$

$2\cdot\left(\cot\left(x\right)\right)^2$