代入到微分方程里去,. y′′+y=cos2x(4C−4Ax−4B)+sin2x(−4A−4Cx−4D)+(Ax+B)cos2x+(Cx+D)sin2x=cos2x(4C−3Ax−3B)+sin2x(−4A−3Cx−3D)=xcos2x y ′ ′ + y = cos ...
確定! 回上一頁