求值:(sin75°-cos75°)/(sin75°+cos75°)
问题描述:
求值:(sin75°-cos75°)/(sin75°+cos75°)
答
√3/3
答
sin75=(√6+√2)/4,cos75=(√6-√2)/4
原式=[(√6+√2)/4-(√6-√2)/4]/[(√6+√2)/4+(√6-√2)/4]=√3/3