a0(x)y′ + a1(x)y = B(x). (1)
a0 ≠ 0 : y′ + a(x)y = b(x), (2)
a(x) = a1(x)/a0(x) b(x) = B(x)/a0(x).
(1) (2) , , .
(1) a0(x) = a0 a1(x) = a1, , (1) . y′ + ay = 0. (3)
: . x. , lny = ax + C, y = eax + C, C ‑ . eC = A, (3) : = Aeax. (4)
A, , (3). , (x1, y1), (4) A. A (4) (3).
, : (3) y(0) = y0. (5)
(3).
(3) (5) , y(x) = y0eax. (6)
, , , x, . , , (4) ( ), y(x1) = y1, .
(3) a = 0, y(x) = C, , (5) y0. y(x) y0 x.
. y′ + ay = b, (b = cost) (7) y(0) = y0.
(, a ≠ 0). (7) z′ + az = 0. , z = z0eax, . , (7) :. (8)
(7) a = 0, y(x) = bx + y0.
. 11.2.
. 11.3.
, (8) : yh = Aeax ‑ y′+ay = 0 y0(x) = b/a ‑ , , (7) y′ = 0. (8) (7) ye yh y(x) . x a < 0 a > 0. (a < 0) , ( ).
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1 2, yh = (y0 ye)eax x a > 0 x a < 0.
. . . p , , . , , S(p). , . D(p). E(p) : E(p) = D(p) S(p). E(p) ≥ 0, , , , D(p) = S(p) E(p) = 0. E(p) ≤ 0, , , . , , : , , . . . k ‑ , .
: D(p) = α + βp S(p) = γ + δp. , p(0) = p0, .
, , , , , β δ <0 β δ >0. β ‑ , δ ‑ , β δ <0 ( ), , . β δ >0, : .
. : ′ + a(x)y = b(x). (9)
a(x) ‑ x. , , b(x) (9) . ′ + a(x)y = 0 ,
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.(10)
A ‑ , y(0) = 0.
. y + 2xy = 0 y(0) = 3.
a(x) = 2 x, A = 3. .
. (10) A = A(x), A x. , (9) , b(x) , . (10) :;.
(9) , :, .
(10), (9):. (11)
. y(1) = 2. (, x = 0, B F.
(11), : , (11).
. (10):. (12)
A, , A = A(x) x. , y , :, , A′(x) = x2 . (12), :. C :.