For all $x\in\mathbb{R}$, Let's define a set $P_x$ as such:
$$P_x=\{y\in\mathbb{R}\,\mid\,y=x^n \text{ for some } n\in\mathbb{N}\}$$
The question is, for $x=\frac{1}{2}$, does $P_x$ contain $0$? As I understand it, $\lim_{n\to\infty}(\frac{1}{2})^n=0$, but does that mean that zero is equal to $\frac{1}{2}$ raised to some $n$?
The set does not contain zero. One way to think about it is that $\frac{1}{2}^n$ is just the product $ \frac{1}{2}\frac{1}{2}\frac{1}{2}...\frac{1}{2},$ $n$ times. Since a product is only zero if one of its factors is zero, and since $\frac{1}{2} \not= 0$, the product is not zero, no matter how large $n$ is. Thus 0 is not in the set.
I hope that helps!!