三角函数公式.求解,谢谢
来源:学生作业帮 编辑:作业帮 分类:综合作业 时间:2024/08/28 10:06:05
三角函数公式.求解,谢谢
喂,图在哪里?还是想列写三角公式啊
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再答: sin(x+y)=sinxcosy-cosxsiny��sin2x=2sinxcosx; cos(x+y)=cosxcosy-sinxsiny;cos2x=2(cosx)^2-1 sin2x+sin2y=2sin(x+y)cos(x-y) sin2x-sin2y=2cos(x+y)sin(x-y) cos2x+cos2y=2cos(x+y)cos(x-y) cos2x-cos2y=-2sin(x+y)sin(x-y) 2sin2xcos2y=sin(x+y)cos(x-y) ̫���ˡ�������������������
再问: ��ǹ�ʽ�������
再答: sin(x+y)=sinxcosy-cosxsiny��sin2x=2sinxcosx; cos(x+y)=cosxcosy-sinxsiny;cos2x=2(cosx)^2-1 sin2x+sin2y=2sin(x+y)cos(x-y) sin2x-sin2y=2cos(x+y)sin(x-y) cos2x+cos2y=2cos(x+y)cos(x-y) cos2x-cos2y=-2sin(x+y)sin(x-y) 2sin2xcos2y=sin(x+y)cos(x-y) ̫���ˡ�������������������