cos83°·cos23°+sin83°·sin23°=
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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
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°=
那位大哥帮帮忙～化简计算：cos23°cos83°＋cos67°sin83°＝＿
sin37°cos83°+cos37°sin83°
为什么sin83°=cos7°
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sin23°cos68°-cos23°sin68°的值
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