令L(D)=2D²+3D-1,y*=1/(2D²+3D-1) sin(2x)sin(2x)是e^(2ix)的虚部,考察y*=1/(2D²+3D-1) e^(2ix)的特解.直接由公式1/L(D) e^(kx)=e^(kx)/L(k)知y*=1/(2D²+3D-1) e^(2ix)=e^(2ix)/[2*(2i)²+3...