sinA / cos(A/2) = sinB / cos(B/2) = sinC / cos(C/2)为什么等于sinA/2=sinB/2=sinC/2

来源：学生作业帮助网编辑：作业帮时间：2024/05/04 07:26:33

sinA / cos(A/2) = sinB / cos(B/2) = sinC / cos(C/2)为什么等于sinA/2=sinB/2=sinC/2
sinA / cos(A/2) = sinB / cos(B/2) = sinC / cos(C/2)为什么等于sinA/2=sinB/2=sinC/2

sinA / cos(A/2) = sinB / cos(B/2) = sinC / cos(C/2)为什么等于sinA/2=sinB/2=sinC/2
sin(x)=2sin(x/2)cos(x/2).代入即得.