Compute cosine similarity between two vectors, a common linear algebra measure of how aligned they are. It’s especially useful when you care about direction more than magnitude.

Requirements

Implement the function

Rules:

• Use the formula: $\cos(x, y) = \frac{\sum_{i=1}^{n} x_i y_i}{\sqrt{\sum_{i=1}^{n} x_i^2}\sqrt{\sum_{i=1}^{n} y_i^2}}$
• Return a single float.
• Do not use any prebuilt similarity/distance utilities (e.g., from scipy).
• Use NumPy for vector operations (np.dot, np.linalg.norm).

Example

Output: