Equation (12.24), from linear supersonic theory, predicts that cd for a flat plate decreases as M increases?

Question:

Equation (12.24), from linear supersonic theory, predicts that cd for a flat plate decreases as M∞ increases? Does this mean that the drag force itself decreases as M∞ increases? To answer this question, derive an equation for drag as a function of M∞, and evaluate this equation.