$\lim_{x\to0}cos\left(x\right)-\frac{cos\left(2x\right)}{x^3}$

$8-[6-\left(-3+7\right)-6]+4$

$\int x^2\cdot e^x.\sin\left(x\right)dx$

$sec\left(-\frac{\pi}{18}\right)cos\frac{37\pi}{18}$

$\int\tan\:\frac{2x}{3}\:dx$

$\frac{5x+10}{2x-2}=4$

$\left(3x^3-y^3+2yx^2\right)\left(2y^2-x^2-3yx\right)$