1、θ=π/3|2a-b|=|(2cosx-√3,2sinx+1)|=√[(2cosx-√3)^2+(2sinx+1)^2]=2√(2+sinx-√3cosx)=2√[2(1+1/2*sinx-√3/2*cosx)]=2√[2(1+sin(x-π/3))]=2√[2(1+cos(5π/6-x))]=2√[2*2cos^2(5π/12-x/2)]=4|cos(5π...