These are all practise questions from my book, i figured out most of them but am stuck on a few. Hoping that someone else can help me
If $\cos(A) + \sin(B) = m$ and $\sin(A) + \cos(B) = n$, prove that $2\sin(a+b) = m^2 + n^2 -2$
I tried to solve it through R.H.S, taking the values of m and n and squaring them.
I got close but i only got $\sin(a+b)$.
I am hoping someone knows how this went wrong, help is highly appreciated!