How to show explicitly that $\{(x, y)| x^3 = y^2\}$ is not a smooth manifold?

105 Views Asked by At

Lately I've been watching a course in differential topology and the instructor gave the set $\{(x, y)| x^3 = y^2\}$ as a subset of $\mathbb{R}^2$ which is not a smooth manifold with no explanation, and I'm wondering how to explicitly show that this set is not a one-dimensional smooth manifold?