sin cos tan三角函数公式大全 1、sin^x+cos^x=1 2、sin(-x)=-sinx 3、cos(-x)=cosx 4、tan(-x)=-tanx 5、sin(x+-y)=sinxcosy+-cosxsiny 6、cos(x+-y)=cosxcosy-+sinxsiny 7、tan(x+-y)=(tanx+-tany)/(1-+tanxtany) 8、sin2x=2sinxcosx 9、cos2x=cos^x-sin^x=2cos^x-1=1-2sin^x 10、tan2x=2tanx/(1-tan^x) 11、sin^x/2=(1-cosx)/2 12、cos^x/2=(1+cosx)/2 13、tan^x/2=sinx/(1+cosx)=(1-cosx)/sinx 14、1-cosx=2sin^x/2 15、1+cosx=2sin^x/2 16、sinx=(2tanx/2)/(1+tan^x/2) 17、cosx=(1-tan^x/2)/(1+tan^x/2) 18、tanx=(2tanx/2)/(1-tan^x/2) 19、sin3x=3sinx-4sin^3 x (sinx的三次方) 20、cos3x=4cos^3 x-3cosx 21、sinxcosy=1/2[sin(x+y)+sin(x-y)] 22、cosxsiny=1/2[sin(x+y)-sin(x-y)] 23、cosxcosy=1/2[cos(x+y)+cos(x-y)] 24、sinxsiny-1/2[cos(x+y)-cos(x-y)] 25、sinx+siny=2sin(x+y)/2cos(x-y)/2 26、sinx-siny=2cos(x+y)/2sin(x-y)/2 27、cosx+cosy=2cos(x+y)/2cos/(x-y)2 本文来源：https://www.wddqw.com/doc/ea5bd0cdbfeb19e8b8f67c1cfad6195f312be888.html