已知tanx=2,则3sin2x+2cos2xcos2x?3sin2x的值为__
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发布时间:2024-10-07 05:17
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时间:2024-10-07 07:04
∵tanx=2,
则3sin2x+2cos2xcos2x?3sin2x=6sinxcosx+2(cos2x?sin2x)cos2x?sin2x?6sinxcosx
=6sinxcosxsin2x+cos2x+2×cos2x?sin2xcos2x+sin2xcos2x?sin2x?6sinxcosxsin2x+cos2x
=6tanx1+tan2x+2×1?tan2x1+tan2x1?tan2x?6tanx1+tan2x
=?715