函数f(X)=2sin(x-π/4)-sin2π的值域为?

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函数f(X)=2sin(x-π/4)-sin2π的值域为?

函数f(X)=2sin(x-π/4)-sin2π的值域为?
函数f(X)=2sin(x-π/4)-sin2π的值域为?

函数f(X)=2sin(x-π/4)-sin2π的值域为?
f(x)=cos(2x-π/3)+2sin(x-π/4)sin(x+π/4)
=cos2xcosπ/3+sin2xsinπ/3+2sin(x-π/4)sin(x+π/4-π/2+π/2)
=1/2cos2x+√3/2sin2x+2sin(x-π/4)cos(x-π/4)
=1/2cos2x+√3/2sin2x+sin2(x-π/4)
=1/2cos2x+√3/2sin2x+sin(2x-π/2)
=1/2cos2x+√3/2sin2x-cos2x
=√3/2-1/2cos2x
=sin(2x-π/6)
(1)
最小正周期:T=2π/2=π
对称轴:
2x-π/6=π/2+kπ(k∈Z)
2x=2π/3+kπ
x=π/3+kπ/2
(2)
2x-π/6=-π/2+2kπ(k∈Z)
2x=-π/3+2kπ
x=-π/6+kπ
2x-π/6=π/2+2kπ(k∈Z)
2x=2π/3+2kπ
x=π/3+kπ
当x=-π/12时,f(x)=-√3/2
当x=π/3是,f(x)=1
f(x)在区间[-π /12,π /2]上的值域 为[-√3/2,1]