f(x)=2sinxcosx-cos(2x-6π)
=sin2x-cos2x
=√2sin(2x-π/2)
最小正周期=2π/2=π
x∈[0,2π/3]时2x-π/2∈[-π/2,5π/5]
因此当2x-π/2=π/2,即 x=π/2时
f(x)最大值等于√2
f(x)=2sinxcosx-cos(2x-6π)
=sin2x-cos2x
=√2sin(2x-π/2)
最小正周期=2π/2=π
x∈[0,2π/3]时2x-π/2∈[-π/2,5π/5]
因此当2x-π/2=π/2,即 x=π/2时
f(x)最大值等于√2