If sin(x) = 3/5 with x in the first quadrant, what is the exact value of sin(2x)?

Answer and explanation

Correct answer: C. 24/25

  1. Step 1: Since sin(x) = 3/5 in Quadrant I, cos(x) = sqrt(1 - (3/5)^2) = 4/5. Step 2. Double angle formula: sin(2x) = 2 sin(x) cos(x). Step 3. sin(2x) = 2 (3/5) (4/5) = 24/25. Answer: 24/25. Why not the others: 6/5 merely doubles 3/5 without cos(x).

Practise more Euclidean Geometry and Trigonometry.

Free questions with an explanation for every one, and full timed University of the Philippines College Admission Test mock tests.