Answer: −7/5.
- A 7/5
- B −7/5
- C 1/5
- D −1/5
Correct answer: B. −7/5
Explanation: In the third quadrant both are negative: sinθ = −3/5, cosθ = −4/5, so the sum is −7/5.
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