赞 5393070123 幼苗
共回答了13个问题采纳率：84.6% 举报
sin(x+x)=sinxcosx+cosxsinx=2sinxcosx
cos(x+x)=cosxcosx-sinxsinx=(cosx)^2-(sinx)^2
另外两个分别加和减1=(sinx)^2+(cosx)^2
sin2x=2sinxcos根据sin(a+b)=sinacosb+cosasinb推出
cos2x=1-(2sinx)^2 or (2cosx)^2-1,同理用
cos(a+b)=cosacosb-sinasinb推导
sin2x
=sin(x+x)
=sinxcosx+cosxsinx
=2sinxcosx
cos2x
=cos(x+x)
=cosxcosx-sinxsinx
=cos^2x-sin^2x
tan2x
=tan(x+x)
=(tanx+tanx)/(1-tanxtanx)
=2tanx/(1-tan^2x)
cos(x+x)=cosxcosx-sinxsinx=(cosx)^2-(sinx)^2
另外两个分别加和减1=(sinx)^2+(cosx)^2
sin2x=2sinxcos根据sin(a+b)=sinacosb+cosasinb推出
cos2x=1-(2sinx)^2 or (2cosx)^2-1,同理用
cos(a+b)=cosacosb-sinasinb推导
sin2x
=sin(x+x)
=sinxcosx+cosxsinx
=2sinxcosx
cos2x
=cos(x+x)
=cosxcosx-sinxsinx
=cos^2x-sin^2x
tan2x
=tan(x+x)
=(tanx+tanx)/(1-tanxtanx)
=2tanx/(1-tan^2x)
1年前
9
qqq7734597 幼苗
共回答了468个问题 举报
sin2x
=sin(x+x)
=sinxcosx+cosxsinx
=2sinxcosx
cos2x
=cos(x+x)
=cosxcosx-sinxsinx
=cos^2x-sin^2x
tan2x
=tan(x+x)
=(tanx+tanx)/(1-tanxtanx)
=2tanx/(1-tan^2x)
=sin(x+x)
=sinxcosx+cosxsinx
=2sinxcosx
cos2x
=cos(x+x)
=cosxcosx-sinxsinx
=cos^2x-sin^2x
tan2x
=tan(x+x)
=(tanx+tanx)/(1-tanxtanx)
=2tanx/(1-tan^2x)
1年前
0
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