已知tan(a+180/4)=2,则cos2a+3sin^2a+tana已知tan(a+180/4)=2,则cos2a+3sin^2a+tan2a

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已知tan(a+180/4)=2,则cos2a+3sin^2a+tana已知tan(a+180/4)=2,则cos2a+3sin^2a+tan2a
已知tan(a+180/4)=2,则cos2a+3sin^2a+tana
已知tan(a+180/4)=2,则cos2a+3sin^2a+tan2a

已知tan(a+180/4)=2,则cos2a+3sin^2a+tana已知tan(a+180/4)=2,则cos2a+3sin^2a+tan2a
1,tan(a+180/4)=tan(a+45)=(tana+tan45)/1-tanatan45=2
tan45=1,解得tana=1/3
sin^2a=1/10
cos2a+3sin^2a+tan a
=1-2sin^2a+3sin^2a+tan a
=1+sin^2a+tan a
=1+1/10+1/3
=43/30

sin是不是有个平方