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Cos80°Cos35°+Cos10°Cos55°=______

∵cos80°cos35°+cos10°cos55°=cos80°cos35°+sin80°sin35°=cos(80°-35°)=cos45°= 2 2 .故答案为: 2 2 .

原式=sin10 ° cos35 ° +cos10 ° sin35 ° =sin(10 ° +35 ° )=sin45 ° = 2 2

原式=sin80º•sin(90º-35º) + cos80º•sin35º =sin80º•cos35º + cos80º•sin35º =sin(80º+35º) =sin115º =sin(90º+25º) =sin25º

详解过程!提供参考

(sin^2(35°)-1/2)/cos10°cos80° =cos70°/2cos10°cos80° =cos70°/(cos90°+cos70°) =1

搞不懂就不用和差化积,用sin倍角公式,稍等

不知道你是要求分开的值还是乘起来的值,如果是后者就简单了。 cos20°cos40°cos80° =2sin20°cos20°cos40°cos80°/2sin20° =sin40°cos40°cos80°/2sin20° =sin80°cos80°/4sin20° =sin160°/8sin20° =sin20°/8sin20° =1/8 谢谢望采纳

=cos(80度-60度) =cos60度 =0.5

解:sin50°(1+√3 tan10°)-cos20°/cos80°√(1-cos20°) =[sin50°(cos10°+√3 sin10°)/cos10°-cos20°]/√2sin²10° =(1-cos20°)/√2sin²10° =√2

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