Question

三角形ABC中若sin(A B)sin(A-B)=sin^2C则三角形ABC是什么三角形

Answer 1

sinC=sin[180-(A+B)]=sin(A+B)

sin(A+B)sin(A-B)=sin²C=sin²(A+B)

sin(A+B)[sin(A-B)-sin(A+B)]=0

因为0