f(x)=2(sinx-cosx)cosx+1
=2sinxcosx-2cos²x+1
=sin2x-cos2x
=√2sin(2x-π/4)
x∈[π/3,3π/4]
2x-π/4∈[5π/12,5π/4]
所以2x-π/4∈[5π/12,π/2] 即x∈[π/3,3π/8]时,单调递增
2x-π/4∈[π/2,5π/4] 即x∈[3π/8,3π/4]时,单调递减
f(x)最大=f(3π/8)=√2
f(x)最小=f(3π/4)=√2*(-√2/2)=-1