If angle x and y are in the same quadrant , and sin x=3/5 and cos y=5/13, determine the value of sin(x-y) .

Answer 1

well, you know that

sinx = 3/5
cosx = 4/5

siny = 12/13
cosy = 5/13

Now just use the identity

sin(x-y) = sinx cosy - cosx siny