解:
dx/dt = x+ sintdx/dt - x = sintletxp = Asint +Bcostxp'= Acost -Bsintxp' - xp= sint(A-B)sint +(A+B)cost =sintA-B =1 (1)A+B=0 (2)(2)-(1)B = -1/2(1)+(2)A= 1/2iex = Ce^(t) + (1/2)sint -(1/2)cost