If sin (A + B) = 1, cos (A – B) = 1 and 0∘<A+B≤90∘, find A and B.
45∘ , 45∘
0∘<A+B≤90∘ (given)
sin (A + B) = 1 only when A + B = 90∘ ………… (1)
cos (A – B) = 1, only when A - B = 0∘ ………… (2)
Adding (1) and (2) we get,
2A = 90∘
So, A = 45∘
and as A - B = 0∘
B = A - 0∘ = 45∘ - 0∘ = 45∘