f(x)=2sin^2(π/4+x)-(√3)cos2x-1
=1-cos(π/2+2x)-(√3)cos2x-1
=sin2x-(√3)cos2x
=2sin(2x-π/3),
x∈[π/4,π/2],
2x-π/3∈[π/6,2π/3],
sin(2x-π/3∈[1/2,1],
f(x)∈[1,2],
|f(x)-m|
f(x)=2sin^2(π/4+x)-(√3)cos2x-1
=1-cos(π/2+2x)-(√3)cos2x-1
=sin2x-(√3)cos2x
=2sin(2x-π/3),
x∈[π/4,π/2],
2x-π/3∈[π/6,2π/3],
sin(2x-π/3∈[1/2,1],
f(x)∈[1,2],
|f(x)-m|