Step 1: {Compute \( f(-x) \)}
\[ f(-x) = \frac{\cos(-x)}{\left\lfloor \frac{2(-x)}{\pi} \right\rfloor + \frac{1}{2}}. \] Using \( \cos(-x) = \cos x \) and property of floor function: \[ \left\lfloor \frac{2(-x)}{\pi} \right\rfloor = - \left\lfloor \frac{2x}{\pi} \right\rfloor - 1. \] Step 2: {Compare \( f(-x) \) with \( -f(x) \)}
\[ f(-x) = -f(x). \] Step 3: {Conclusion}
Since \( f(-x) = -f(x) \), the function is odd.