hello there iwas wandering if someone out there could help me.
i have been given a problem and i am really struggling to resolve a solution
if sin A + sin B = X
cos A + cos B = y
then prove sin (A+B)= (2xy)/(x^2+y^2)
if you can help thankyou
i have been trying to use the formula
a sin x+ b cos x = y =cos (x+z) to no avail haha