sin75度＋sin15度等于多少?
问题描述：
sin75度＋sin15度等于多少?
答
根号6/2
答
sin75°＋sin15°
＝2sin45°cos30°
＝2×√2/2×√3/2
＝√6/2
sin75°＋cos75°
答
sin75＋sin15
=sin(45+30)+sin(45-30)
=sin45cos30+cos45sin30+sin45cos30-cos45sin30
=2*sin45cos30
=2*(根号2/2)*(根号3/2)
=根号6/2
答
sin(A/2)=√[(1-cosA)/2]
sin75°+sin15°=√[(1-cos150°)/2]+√[(1-cos30°)/2]
=√6/2
答
sin75+sin15=2sin(90/2)cos(60/2)=2*√2/2*√3/2=√6/2