来自刘庆丰的问题
若A+B=2π3,则cos2A+cos2B的值的范围是()A.[0,12]B.[12,32]C.[12,1]D.[0,1]
若A+B=2π3,则cos2A+cos2B的值的范围是()
A.[0,12]
B.[12,32]
C.[12,1]
D.[0,1]
1回答
2020-06-16 00:16
若A+B=2π3,则cos2A+cos2B的值的范围是()A.[0,12]B.[12,32]C.[12,1]D.[0,1]
若A+B=2π3,则cos2A+cos2B的值的范围是()
A.[0,12]
B.[12,32]
C.[12,1]
D.[0,1]
∵y=cos2A+cos2B=12