1. Fundamental Trigonometric Identity: Apply the Pythagorean trigonometric identity:
2
sin²(x) + cos²(x) = 1
3
2. 💡 Real-world Application: 📌 In physics, trigonometric identities are used to simplify equations describing waves and oscillations (e.g., sound waves, light waves, AC circuits). In engineering, they enable engineers to analyze and design systems involving rotational or periodic motion.