cos2a-1+2sin^2a
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cos2a-1+2sin^2a
怎么化简哦
怎么化简哦
![cos2a-1+2sin^2a](/uploads/image/z/8554856-32-6.jpg?t=cos2a-1%2B2sin%5E2a)
cos 2a=cos(a+a) =cos a*cos a -sina *sina = (1-sin^2a)- sin^2a =1-2sin^2a
所以 cos2a-1+2sin^2a =1-2sin^2a-1+2sin^2a =0
所以 cos2a-1+2sin^2a =1-2sin^2a-1+2sin^2a =0
cos2a-1+2sin^2a
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