高数 齐次方程 求通解 求过程

2024-11-23 22:26:31
推荐回答(2个)
回答1:

最后一步错了改下,应该是(x-1)的平方,看懵了我!自己化简下!

回答2:

联立解 x-y+1 = 0, x+y-3 = 0 , 得 (1,2)
作变换 x = X+1, y = Y+2,
原来的准齐次方程化为齐次方程 dY/dX = (X-Y)/(X+Y),
令 Y = XU, 则 U+XdU/dX = (1-U)/(1+U)
XdU/dX = (1-2U-U^2)/(1+U)
(1+U)dU/(1-2U-U^2) = dX/X
d(1-2U-U^2)/(1-2U-U^2) = -2dX/X
ln(1-2U-U^2) = -2lnX+lnC
1-2U-U^2 = C/X^2
X^2-2XY-Y^2 = C
通解是 (x-1)^2 - 2(x-1)(y-2) - (y-2)^2 = C