cos(X-cosX)=sin(π/2-X+cosX)带入原式sin(x+sinx)=sin(π/2-x+cosx)x+sinx=π/2-x+cosxsinx-cosx=π/2-2x对于原式左侧有sinx-cosx=√2(√2/2*sinx-√2/2cosx)=√2(sinxcosπ/4-cosxsinπ/4)=√2sin(x-π/4)∴√2sin(x-π/4)=π/2-2x将x=π/4带入,易得原方程两侧都等于0∴满足原方程的x∈(0,π/2)存在且x=π/4