f(x)=a·b=(1+sin(2x),sinx-cosx)·(1,sinx+cosx)=1+sin(2x)+(sinx-cosx)(sinx+cosx)=1+sin(2x)+sinx^2-cosx^2=1+sin(2x)-cos(2x)=1+√2sin(2x-π/4)sin(2x-π/4)∈[-1,1]√2sin(2x-π/4)∈[-√2,√2]故：f(x)∈[1-...