2、数学(tan5度-cot5度)*sin20度/(1+cos20度)=()?

问题描述:

2、数学(tan5度-cot5度)*sin20度/(1+cos20度)=()?
(tan5度-cot5度)*sin20度/(1+cos20度)=()?
2 ,我做不出来~

(TAN5度-COT5度).SIN20度/(1+COS20度) 先化简:TAN5度-COT5度=(sin^2 5-cos^2 5)/sin5cos5=2(sin^2 5-cos^2 5)/sin10 再化简:(TAN5度-COT5度).SIN20度=2(sin^2 5-cos^2 5)/sin10*(2sin10cos10)=4(sin^2 5-...