化简cos(80°)/1-cos(10°) =

化简cos(80°)/1-cos(10°) =
化简cos(80°)/1-cos(10°) =

化简cos(80°)/1-cos(10°) =
cos(80°)/1-cos(10°)=sin(10°）/{1-(1-2（sin5°）^2}=2sin5°cos5°/2（sin5°）^2=cot5°
如有不明白,

cos80=sin10=2sin5cos5
1-cos10=2cos²5
所以原式=2sin5cos5/(2cos²5)=sin5/cos5=tan5

cos(80°)/【1-cos(10°)】 =sin10°/{1-【1-2（sin5°）^2】}=2sin5°cos5°/（2sin5°*sin5°）=cot5°（=tan85°）