sin(2x)/1+cos(2x)=3/4,求tan(x/2)的数学题
来源:百度知道 编辑:UC知道 时间:2024/09/21 05:04:55
2sinxcosx/2cos^2x=3/4
tanx=3/4
tan2A=2tanA/(1-tanA^2)
3/4=2tan(x/2)/(1-tan^2(x/2))
3-3tan^2(x/2)=8tan(x/2)
3tan^2(x/2)+8tan(x/2)-3=0
(3tan(x/2)-1)(tan(x/2)+3)=0
tan(x/2)=1/2
tan(x/2)=-3
sin(2x)/1+cos(2x)=3/4
=tanx
tanx=2tan(x/2)/(1-tan(x/2)^2)=3/4
2tan(x/2)=3/4-3/4tan(x/2)^2
8tan(x/2)=3-3tan(x/2)^2
3tan(x/2)^2+8tan(x/2)-3=0
tan(x/2)=-3或1/3
哎!都忘光了
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