高中数学化简题sin50°(1+根号3)=
问题描述:
高中数学化简题
sin50°(1+根号3)=
答
是这二个吗?
sin50°(1+√3×cot80°)
=sin50[sin80+√3×cos80]/sin80
=2sin50{(1/2)cos80+(√3/2)sin80}/sin80
=2sin50cos50/sin80
=sin100/sin80
=sin80/sin80
=1
sin50°[1+(√3)×tan10°]
=sin50×[(√3)sin10+cos10]/cos10
=(sin50/cos10)×2×(cos30sin10+cos10sin30)
=(sin50/cos10)×2×sin40
=2×sin50×cos50/cos10
=sin100/cos10
=cos10/cos10
=1