Question

If sin (A – B) = 1/2,
cos (A + B) = 1/2,
0° < A + B ≤ 90°,
A > B,
find A and B.

Answer 1

sin(A-B)=sin30  { ..sin1\2 =  30  }
cos (A+B) =cos  90 {since cos 1\2=90}
A-B=30.....................1
A+B=90....................2
FROM Eq 1 and 2 we have ;
A-B=30
A+B=90

             2A=120
A=60
SUBTITUTE THE VALUE OF A IN A-B=30 WE GET ;
60-B=30
-B=30-60
-B=-30
B=30
                   ANS = A=60 B=30