高数求微分方程解 求详细过程

2024-11-23 15:29:11
推荐回答(2个)
回答1:

转成标准型    y'-(2/x)y=2   


p(x)=-2/x    g(x)=2


套公式  积分  exp(∫-(2/x)dx)=exp(2ln|x|)=x²



积分 ∫2/x² dx=-2/x


所以y=x²【C-2/x】=Cx²-2x

回答2:

let

u = y/x^2
du/dx = (1/x^2) dy/dx - 2(y/x^3)
dy/dx = x^2.[du/dx + (2/x)u ]
//
x.dy/dx -2y = 2x
dy/dx - 2(y/x) = 2
x^2.[du/dx + (2/x)u ] - 2xu =2
x^2.du/dx = 2
u = 2 ∫ dx/x^2
= -2/x + C
y/x^2 = -2/x +C
y= -2x + Cx^2