Question 969488
Find each value if sin A = 12/13 with 90 degrees <= A <= 270 degrees and if sin B = -7/25 with -90 degrees <= B <= 90 degrees. 
1. sin(A + B)
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sinA=12/13 (90 < A < 270)
cosA=-5/13
..
sinB=-7/25 (-90 < B < 90)
cosB=24/25
sin(A+B)=sinAcosB+cosAsinB=12/13*24/25+-5/13*-7/25=288/325+35/325=323/325
..
Check:
sinA=12/13 (Q2)
A&#8776;112.62
sinB=-7/25 (Q4)
B&#8776;343.74
A+B=456.36
sin(A+B)=sin(456.36)&#8776;0.9938
exact value as computed=323/325&#8776;0.9938