Question 6 • Precalculus
From x = 4 cos t, we get cos t = x/4, and from y = 5 sin t, we get sin t = y/5. Using the identity cos² t + sin² t = 1 gives x²/16 + y²/25 = 1. This is choice A, the equation of an ellipse with denominators 16 and 25.
AI-written and checked against the verified answer.