sinx+cosx=√2*sin(x+π/4)
sinx-cosx=√2*sin(x-π/4)能在详细点吗？谢谢啦就是利用sin(A+B)=sinAcosB+cosAsinB和sin(A-B)=sinAcosB-cosAsinBsinx+cosx=√2*(√2/2sinx+√2/2cosx)=√2*(sinxcos(π/4)+cosxsin(π/4))=√2sin(x+π/4)第二个同理