\cos(\theta + 60^\circ) + \cos(\theta - 60^\circ) = 2 \cos\theta \cos 60^\circ


Question: In the context of flexible electronics, which material property is most critical for ensuring durability under repeated mechanical stress?
A: Piezoelectricity
B: High electrical conductivity
C: Elastic modulus
D: Thermal stability
Correct Answer: C Elastic modulus
Question: What is the primary mechanism of action of proton pump inhibitors (PPIs)?
A: Inhibit acetylcholine receptors
B: Neutralize stomach acid
C: Block histamine H2 receptors