有關Bcos2的精選大全

等於(  )(A)sin2-cos2                         (B)cos2-sin2...
問題詳情:等於()(A)sin2-cos2                         (B)cos2-sin2(C)±(sin2-cos2)              (D)sin2+cos2【回答】A.原式===|sin2-cos2|,∵sin2>0,cos2<0,∴原式=sin2-cos2.知識點:...
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