sinA+sinB=2sin(A+B/2)cos(A-B/2)咋证?

来源：学生作业帮助网 编辑：作业帮 时间：2024/06/06 07:14:03

sinA+sinB=2sin(A+B/2)cos(A-B/2)咋证?
sinA+sinB=2sin(A+B/2)cos(A-B/2)咋证?

sinA+sinB=2sin(A+B/2)cos(A-B/2)咋证?