sinθ+cosθ=√2(sinθsin(π/4)+cosθcos(π/4))=√2cos(θ-π/4)如果是加号，那么应该是sinsinθ+cosθ=√2(sinθcos(π/4)+cosθsin(π/4))=√2sin(θ+π/4)
这个为什么要化简啊
