Please check the first one for typos . . .
Note: If , the denominator is: .
. . That is: . . . We can cancel this
We have: .
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))^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