To prove the periodicity of the state of simple harmonic motion, one can start by analyzing the function Y(x) given in the discussion. The periodic nature can often be established by demonstrating that Y(x + T) = Y(x) for some period T. The approach involves examining the terms in the expression, particularly the exponential components, to identify their periodic characteristics. Utilizing the relationship f(x + t) = f(x) can help in this analysis, although the specific application may require careful manipulation of the terms. Understanding the underlying mathematical properties of the components is crucial for proving periodicity.