2020 · Q63
If θ lies in the first quadrant and cotθ = 63/16, then what is the value of (sin θ + cos θ)?
Elementary MathematicsTrigonometry
- A1
- B69/65
- C79/65
- D2
Explanation
cotθ = 63/16 in the first quadrant gives a 16–63–65 triangle: sinθ = 16/65, cosθ = 63/65. Their sum is 79/65. The 16–63–65 triple checks out since 63² + 16² = 4225 = 65².