Problem
14. Which of the following is equal to $\left(\sin 60^{\circ} \sin 30^{\circ}\right)-\left(\cos 30^{\circ} \cos 60^{\circ}\right)$ ? I. $1 / 2$ II. 1 III. 0 IV. $\sqrt{2}$ A. I only B. II only C. III only D. IV only
Solution
Step 1 ：Calculate the value of \(\left(\sin 60^{\circ} \sin 30^{\circ}\right)-\left(\cos 30^{\circ} \cos 60^{\circ}\right)\)
Step 2 ：The result is very close to 0, so the final answer is \(\boxed{0}\)
