已知函数y=Asin(ωx+φ)(A>0,ω>0,|φ|<π/2)

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已知函数y=Asin(ωx+φ)(A>0,ω>0,|φ|<π/2)
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已知函数y=Asin(ωx+φ)(A>0,ω>0,|φ|<π/2)
已知函数y=Asin(ωx+φ)(A>0,ω>0,|φ|<π/2)
 

已知函数y=Asin(ωx+φ)(A>0,ω>0,|φ|<π/2)
(1)解析:由图所示:T=11π/12+π/12=π==>ω=2π/T=2,A=2
∴函数f(x)=2sin(2x+φ)
f(x)=2sin(2x+φ)==> f(-π/12)=2sin(-π/6+φ)=0==>φ=π/6
∴f(x)=2sin(2x+π/6)
(2)解析:g(x)=f(x-π/4)=2sin(2x-π/2+π/6) =2sin(2x-π/3)
设cosθ=(1+√3)/(2√2),sinθ=(1-√3)/(2√2)
F(x)+g(x)= 2sin(2x+π/6)+ 2sin(2x-π/3)=2√2sin(2x+θ)
∵y=√6,区间(0,π)
2√2sin(2x+θ)= √6==> sin(2x+θ)= √3/2==>2x+θ=π/3==>x=(π-3θ)/6;2x+θ=2π/3==>x=(2π-3θ)/6
∴直线y=√6与函数y=f(x)+g(x)图像在(0,π)内交点为((π-3θ)/6,√6),((2π-3θ)/6,√6)

1.最大值为2
则A=2
T =2π/ω=π/2
所以ω=4
y=2sin(4x+φ)
x=π/3是其图象的一条对称轴
所以 x=π/3时,y有最大值或最小值
所以 4*π/3+φ=kπ+π/2
φ=kπ-5π/6
因为 0<φ<π
所以 φ=π/6,(k=1)
所以 y=2sin(4x+π/6)