1. The problem is to understand the expression $\cos x \sin x$. 2. This is a product of the cosine and sine trigonometric functions. 3. We can express $\cos x \sin x$ using the double-angle identity for sine: $$\sin(2x) = 2 \sin x \cos x$$ 4. Therefore, $$\cos x \sin x = \frac{\sin(2x)}{2}$$ 5. So the expression $\cos x \sin x$ is equal to half of $\sin(2x)$.