How would I prove these identities?

1) sin(A+B)*sin(A-B)=(sin A)^2*(sin B)^2

I've gotten to expanding it to

(sin(A)cos(B)+sin(B)cos(A))*(sin(A)cos(B)-sin(B)cos(A))

then

(sin(A)cos(B))^2-(sin(B)cos(A))^2, but I'm not sure what to do next

2) (cos W-sin 2W)/(cos 2W+sin W-1)=cot W