Answer: cos θ.
- A tan θ
- B cosec θ
- C cos θ
- D sec θ
Correct answer: C. cos θ
Explanation: tan θ = sin θ / cos θ (definition of tangent in terms of sine and cosine).
Unit circle with standard angles 0, 30, 45, 60, 90 degrees; at 45 degrees the point is (cos45, sin45) = (1/sqrt2, 1/sqrt2).
Concept context
Ratios, identities, and applications in triangles