你题目是f(x)=5cosx(sinx-√3cosx）+5/2√3吧?f(x)=5cosx(sinx-√3cosx）+5/2√3 =5cosxsinx-5√3cosxcosx+5/2√3 =5/2sin2x-5/2√3(cos2x+1)+5/2√3 =5/2(sin2x-√3cos2x) =5(1/2sin2x-√3/2cos2x) =5sin(2x-π/3)...你题目是f(x)=5cosx(sinx-√3cosx）+5/2√3吧？f(x)=5cosx(sinx-√3cosx）+5/2√3 =5cosxsinx-5√3cosxcosx+5/2√3 =5/2sin2x-5/2√3(cos2x+1)+5/2√3 =5/2(sin2x-√3cos2x) =5(1/2sin2x-√3/2cos2x) =5sin(2x-π/3)