Given Tan(A) = 5 in Quadrant III and Sin(B) = ⅔ in Quadrant II, find Sin(A-B).

1 answer

Draw your triangles and quickly see that

sinA = -5/√26
cosA = -1/√26

sinB = 2/3
cosB = -√5/3

now just use your sum-of-angles formula for sin(A-B)