2023 · Q23
If 3sin θ + 5cos θ = 5, then what is the value of 5sin θ − 3cos θ equal to?
Elementary MathematicsTrigonometry
- A5
- B−3
- C−2
- D0
Explanation
Square: (3 sin+5 cos)^2=25 gives 9sin^2+25cos^2+30 sin cos=25; with sin^2+cos^2=1 this yields (5 sin-3 cos)^2=9. The listed admissible value is -3. Option (b).