Sin (A + B) = - sin C

A + B = 2κπ - C, κ∈Z or A + B = 2κπ + π + C, κ∈Z

Step-by-step explanation:

sin (A + B) = - sin C

sin (A + B) = sin ( - C)

A + B = 2κπ + (-C), κ∈Z or A + B = 2κπ + π - (-C), κ∈Z

A + B = 2κπ - C, κ∈Z or A + B = 2κπ + π + C, κ∈Z

where:

κ is an integer π is pi, the well known 3,14 ...