2009 · Q10
If sin x + sin y = a and cos x + cos y = b, what is sin x . sin y + cos x . cos y equal to?
Elementary MathematicsStatistics
- Aa + b- ab
- Ba + b + ab
- Ca 2 +b 2 -2
- D(a 2 +b 2 -2)/2
Explanation
Solved; answer D.
If sin x + sin y = a and cos x + cos y = b, what is sin x . sin y + cos x . cos y equal to?
Explanation
Solved; answer D.