sinx/2+cosx/2=2√3/3平方
sin^2 x/2 +2sinx/2cosx/2+cos^2 x/2=4/3
1+sinx=4/3
sinx=1/3
cos2x=1-2sin^2 x=1-2*(1/3)^2=1-2/9=7/9
已知sinx/2+cosx/2=2根号3/3,则sinx= ,cos2x= (“/”为除号)
已知sinx/2+cosx/2=2根号3/3,则sinx= ,cos2x= (“/”为除号)
数学人气:372 ℃时间:2019-08-20 15:36:43
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