Without the image, I can't determine the exact curve you're referring to. However, the general form of a square root function is:
\[ f(x) = a \sqrt{x - h} + k \]
where:
- \( a \) is a vertical stretch or compression and reflection,
- \( (h, k) \) is the vertex of the parabola represented by the square root function.
If you can describe specific features of the graph, such as the vertex or any intercepts, I can help derive the exact equation of Rhianna's square root function.