(1)角A>角B是sinA>sinB的充分条件角A>角B 则 边a>边b (大角对大边)边a>边b,根据正弦定理知:a/ sinA =b/ sinB 则 sinA>sinB .(2)角A>角B是sinA>sinB的必要条件类似可证:已知sinA>sinB,根据正弦定理知:a/ sinA =b/...