$\lim_{x\to0}\left(\frac{\cos\left(x+1\right)-\cos\left(x-1\right)}{x}\right)$

$\frac{1}{4}a-\frac{3}{5}a^2+\frac{1}{3}a^2$

$3\sin^2\left(0\right)+5\cos\left(0\right)-1$

$\left(m^4-m^2-m\right)\left(m^4-m^2+m\right)$

$arctan\left(tan\left(\frac{56}{45}\pi\right)\right)$

$\left(6^2+1\right)\left(6^4+1\right)\left(6^8+1\right)$

$18-2x>4$