作业帮cos83°·cos23°+sin83°·sin23°=
来源：学生作业帮助网 编辑：作业帮 时间：2024/07/16 23:46:10
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cos83°·cos23°+sin83°·sin23°=
cos83°·cos23°+sin83°·sin23°=
cos83°·cos23°+sin83°·sin23°=
原式=1/2
∵由公式：cos(α-β) = cosαcosβ + sinαsinβ
∴cos83°·cos23°+sin83°·sin23° = cos(83° - 23°) = cos60° = 1/2
cos83°·cos23°+sin83°·sin23°=cos﹙83-23﹚º=cos60º=0.5
cos83°·cos23°+sin83°·sin23°=
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