cos(三分之二派加二阿法)等于多少
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发布时间:2024-10-06 00:52
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热心网友
时间:2024-11-20 13:29
cos(2π/3+2α)
=cos(2π/3)cos(2α)-sin(2π/3)sin(2α)
=-1/2cos(2α)-√3/2sin(2α)
=-1/2(cos^2α-sin^2α)-√3/2×2sinαcosα
=-1/2cos^2α+1/2sin^2α-√3sinαcosα
注:^2——表示平方。
热心网友
时间:2024-11-20 13:30
解: cos(2π/3+2α)
=cos2[(π/3+α)]
=2cos²(π/3+α)-1
=2[cosπ/3 cosα-sinπ/3 sinα]²-1
=2(cosα/2-√3/2 sinα)²-1
=1/2(cosα-√3sinα)²-1
=1/2(cos²α-2√3sinαcosα+3sin²α)-1
=1/2(1+2sinα²-2√3sinαcosα)-1
=sin²α-√3sinαcosα-1/2
热心网友
时间:2024-11-20 13:30
cos(pi*2/3+2a)使用公式展开即可