Final answer:
The correct mathematical expression that involves the subtraction of two angles is sin(B-C), which matches the known trigonometric identity for the sine of the difference between two angles.
Step-by-step explanation:
The question asks which mathematical expression involves the subtraction of two angles. Analyzing the given options, we see that sin(B-C) represents the sine of the difference between two angles B and C. This aligns with one of the trigonometric identities, specifically the formula for the sine of the subtraction of two angles:
sin (a ± β) = sin a cos β ± cos a sin β
Thus, option C, sin(B-C), is the correct answer. It should be noted that although trigonometric identities involving the subtraction of angles were mentioned in the provided reference information, the exact expression sin(B-C) was not directly listed but can be inferred from the known trigonometric identities.