$$4x^2-12xy^3+9y^6$$

$$\cos\left(a\right)=\cos\left(a\right)\sin\left(a\right)$$

$$4x+5y=5y+4x$$

$$3-\left(+5-\left|-11-\left(-2-1\right)+2\right|+8\right)+9$$

$$\frac{2x+4}{x\left(x+4\right)}$$

$$\lim_{x\to\frac{\pi}{4}}\left(\frac{1-\tan\left(x\right)}{\cos\left(2x\right)}\right)$$

$$\lim_{n\to200}\left(\sin\left(n\pi\right)\right)$$