$\frac{d}{dx}-cos\frac{x}{e^2}.cot\frac{x}{e^2}$

$4-32+54-20+8-9$

$\:\left(m+3n^2+4\right)^2$

$35\:x\frac{2}{7}$

$\lim_{x\to-\infty}\left(\arctan\left(0\right)-\arctan\left(x\right)\right)$

$x\left(x+2y\right)+y^2$

$13-\sqrt{64}\cdot\left(7^2\left(3-6\right)+2\right)$