高一数学,三角函数,求完整过程,谢谢
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f(x)=sin(2x+θ)+√3cos(2x+θ)
=2sin(2x+θ+π/3)
(2)0≤θ≤π
f(-x)=2sin(-2x+θ+π/3)=-2sin(2x-θ-π/3)=2sin(π+2x-θ-π/3)=2sin(2x-θ+2π/3)=f(x)
∴-θ+2π/3=θ+π/3→θ=π/6
(3)f(x)=-2cos2x
y=4sinx-2cos2x=4sinx-2(1-2sin²x)=4sin²x+4sinx-2=4(sinx+1/2)²-3
∴x=-π/6 y取得最小值=-3
x=π/2 y取得最大值=6
=2sin(2x+θ+π/3)
(2)0≤θ≤π
f(-x)=2sin(-2x+θ+π/3)=-2sin(2x-θ-π/3)=2sin(π+2x-θ-π/3)=2sin(2x-θ+2π/3)=f(x)
∴-θ+2π/3=θ+π/3→θ=π/6
(3)f(x)=-2cos2x
y=4sinx-2cos2x=4sinx-2(1-2sin²x)=4sin²x+4sinx-2=4(sinx+1/2)²-3
∴x=-π/6 y取得最小值=-3
x=π/2 y取得最大值=6
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