Limit of product of cosines: $\lim\limits_{n \to \infty} \cos(\frac{x}{2})\cos(\frac{x}{4})\cos(\frac{x}{6})\cdots\cos(\frac{x}{2^n})$
Finding the limit $\lim \limits_{n \to \infty}\ (\cos \frac x 2 \cdot\cos \frac x 4\cdot \cos \frac x 8\cdots \cos \frac x {2^n}) $