A(x)y"+B(x)y+C(x)y=F(x) (1) If F(x)=0,(1)is a homogeneous linear equation;otherwise, nonhomogeneous. Example x2y"+2xy+3y-cosx=0 (nonhomogenous) x2y"+2y+3y=0 4日10y至，无2000A(x)y 00 +B(x)y 0 +C(x)y = F(x) (1) If F(x) ≡ 0, (1) is a homogeneous linear equation; otherwise, nonhomogeneous. Example x 2 y 00 +2xy 0 +3y−cos x = 0 (nonhomogenous) x 2 y 00 +2xy 0 +3y = 0 (homogeneous)