Which identity is the correct product-to-sum formula for sin(A)cos(B)\sin(A)\cos(B)sin(A)cos(B)?
12[sin(A+B)+sin(A−B)]\frac{1}{2}[\sin(A+B) + \sin(A-B)]21[sin(A+B)+sin(A−B)]
12[cos(A+B)+cos(A−B)]\frac{1}{2}[\cos(A+B) + \cos(A-B)]21[cos(A+B)+cos(A−B)]
12[sin(A+B)−sin(A−B)]\frac{1}{2}[\sin(A+B) - \sin(A-B)]21[sin(A+B)−sin(A−B)]
sin(A+B)+sin(A−B)\sin(A+B) + \sin(A-B)sin(A+B)+sin(A−B)