Answer:
-2 cos x * sin y
Step-by-step explanation:
Use the trigonometric formula
sin (a±b) = (sin a *cos b ± cos a *sin b)
sin(x − y) − sin(x + y) =
(sin x *cos y - cos x *sin y) - (sin x *cos y + cos x *sin y)=
distribute the "-" in parenthesis
sin x *cos y - cos x *sin y - sin x *cos y - cos x *sin y =
combine like terms
-2 cos x * sin y
