# If sin a + sin b = 2 , then find the value of cos a + cos b

Shaswata Biswas
132 Points
6 years ago
We know $-1\leqslant \sin a\leqslant 1$, and $-1\leqslant \sin b\leqslant 1$
Here, sina + sinb = 2
It is only possible when sina = sinb = 1.
=> a = b = π/2
So the value of cosa + cosb = cos(π/2) + cos (π/2) = 0.
THANKS