Answer: cos θ.
- A sin θ
- B cos θ
- C tan θ
- D cot θ
Correct answer: B. cos θ
Explanation: sec θ = 1/cos θ (secant is the reciprocal of 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