已知函数f(x)=sinx+sin(x+2/3π)(x∈R )(1)函数y=f(x)的图像的二相邻对称轴之间的距离 (2)函数f(x)=1/3,求cos(2x+2/3π)的值 注:

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已知函数f(x)=sinx+sin(x+2/3π)(x∈R )(1)函数y=f(x)的图像的二相邻对称轴之间的距离 (2)函数f(x)=1/3,求cos(2x+2/3π)的值 注:
已知函数f(x)=sinx+sin(x+2/3π)(x∈R )
(1)函数y=f(x)的图像的二相邻对称轴之间的距离 (2)函数f(x)=1/3,求cos(2x+2/3π)的值 注:

已知函数f(x)=sinx+sin(x+2/3π)(x∈R )(1)函数y=f(x)的图像的二相邻对称轴之间的距离 (2)函数f(x)=1/3,求cos(2x+2/3π)的值 注:
f(x)=sinx+sin(x+2π/3)
=simx+simxcos2π/3+cosxsin2π/3
=sinx-1/2sinx+√3/2cosx
=1/2sinx+√3/2cosx
=sin(x+π/3)
(1)∵T=2π,∴相邻两个对称轴之间的距离是π;
(2)f(x)=1/3,即sin(x+π/3)=1/3,
∴cos(2x+2π/3)=cos2(x+π/3)=1-2sin²(x+π/3)=1-2/9=7/9

(1)f(x)=sinx-1/2sinx+√3/2cosx=1/2sinx+√3/2cosx=sin(x+π/3)
∴最小正周期T=2π
∴二相邻对称轴之间的距离:T/2=π
(2)f(x)=sin(x+π/3)=1/3
∴cos(2x+2π/3)=1-2sin²(x+π/3)=1-1/9=8/9

(1)f(x)=sinx+sinx*(-1/2)+根号3/2cosx
=1/2sinx+根号3/2cosx
=sin(x+π/3)
则周期为2π,两相邻对称轴之间距离为π
(2)f(x)=sin(x+Pai/3)=1/3
推出cos(2x+2π/3)=1-2(sin(x+π/3))^2=7/9第一...

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(1)f(x)=sinx+sinx*(-1/2)+根号3/2cosx
=1/2sinx+根号3/2cosx
=sin(x+π/3)
则周期为2π,两相邻对称轴之间距离为π
(2)f(x)=sin(x+Pai/3)=1/3
推出cos(2x+2π/3)=1-2(sin(x+π/3))^2=7/9

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