l=\lim_{x\to 0}(\frac{(x-2sin\frac{x}{2}+4sin\frac{x}{2}(sin\frac{x}{4})^{2})}{x^{3}} \frac{(x+2sin\frac{x}{2}+4sin\frac{x}{2}(sin\frac{x}{4})^{2})}{x}