dy = y ¢ dx,
y = c 1 x ¾ .
2. ,
= 1 + 2 2 (1)
" 3 ' + 2 = 0. (2)
. (1), :
y' = 1 + 2 2 2 ,
" = 1 + 4 2 2 .
1 2 2 , :
1 = 2y' ",
(1), (2).
3. ,
3 3 + 3 = 0 (3)
3 ( 2 + 2) ' + 2 = 0. (4)
. (3) , = (),
2 ' 2 + + ' = 0,
2 = ( 2 + ) ' + .
2 (3), :
3 ( 2 y' + y' + y) x + 3 = 0,
(4).
4.
y = C (x C)2. (5)
. (5) ,
y' =2 C (x C), (6)
2= 5'. (7)
(7) (5) , :
=0,5 ' 0,5 '.
,
' = ' 2 . (8)
(6) (')2,
(')3=2 ' (') 2(')2.
' (8), :
(')3=4 y' 8y 2.
5.
(0) = 1.
. <>, , :
,
, 1 = 1 + , = 0. , :
, (0, 1). ►
6. :
yx2dy ln xdx = 0. (10)
.
. (11)
, (11) :
. ,
= ln x,:
(10) :
7.
. 0 ,
. z = / , z = z (). ' = zx y'=z'x + z, (12.13) :
.. . ,
, :
8:
1) (1 + x2)y" 2' = 0.
y' = p, p = p (x), y'' = p' Þ (1+ 2) p' 2 =0 Þ
|
|
y' = c 1(1 + x 2) Þ dy = c 1(1 + x 2) dx Þ
y = c 1(x + x 3/3) + c 2. ►
2) 1 + y'2 = 2y''.
y' = p, p = p(y), " = ', 1 + 2 =2'
9:
y" = y' ctg x.
. z = 1. " = (') ' = z'
z' = z ctg x. (12.28)
z ≠ 0. (12.28) :
,
ln|z| = ln|sin x| + lnC1,
1 > 0,
z = 1sin x.
z = 0 (12.28), :
z = 1sin x, (12.29)
1 .
(12.29) :
dy = 1sin xdx.
,
= 1cos x + C2. ►
10:
yy" = y2y' + (y')2,
. z = y', , : dy
yzz' = y 2 z + z 2, (12.30)
.. z = z(y). , z = 0 (12.30), = , .
z ≠0. (12.30) ,
yz' = y2 + z (12.31)
. z = uv, v = v (y)
yv' v = 0, (12.32)
= ()
u'v = y. (12.33)
(12.32), , v = . (1233) ' =1, = + 1, .. (12.31) :
z = y 2+ C ] y.
z = y',
1 = 0. y ≠0
, , = 1 + 2,
=( 2 ) 1. (12.34)
C1 ≠ 0,
:
= (12.34), (1235)
11.
xy ¢ - y - x - 1 = 0.
y = x ln x + Cx - 1 ¾ .
12.
.
= × v,
v = v (x)
u = u (x)
vu' = x 2. (12.19)
(12.18) :
, :
ln|v| = ln|x + 1| + C.
(12.18), =0,
v (12.19),
du = (x 3 + x 2) dx.
, :
13.
( 3 ) ' = 1.
. x = () (.. , , ).
:
' + = 3. (12.20)
:
' + = 0. (12.21)
≠ 0.
, = 0 (12.21),, :
12.22
, 2= 2(), , (12.22) (12.20). (12.22) ,
|
|
12.23
(12.22), (12.23) (12.20),
, :
2= 2() (12.22), (12.20):
14.
. n = 2. , = 0 . ≠ 0. z = 1 n = 1. = z 1, ' = z 2 z' :
z ≠ 0.
ln|z| = ln|x| = lnC2, (12.26)
2 . (12.26) :
| z | = 2| | z = 2 .
, z = 0 (12.25), , :
z = 1 ,(12.27)
1 .
, 1 = 1() 1 , (12.27) (12.24). (12.27) ,
, (12.27), , (12.24) :
dC 1 = dx,
1 = + .
(12.27), (12.24):
z = (x + C) x.
:
( 2+ ) = 1,
y = 0.
15. :
) y'' 3 y' + 2 y = 0;
λ2 3λ + 2 = 0,
λ1 = 1, λ2 = 2.
y = C 1 ex + C 2 e 2 x .
) y'' 2 y' + y = 0
λ2 2λ + 1 = 0
λ1 = λ2 = 1
. 2
y = (C 1 + C 2 x) ex.
) y'' 2 y' + 2 y = 0.
λ2 2λ + 2 = 0
. . 3
y = C1exsin x + C2excos x (a = β = 1).
16.
¾ .
¾ .
¾ .
:
sin x cos x.
¾ .
¾ .
17.
" + ' = 5 + 3. ◄
.
) y *
" + ' = 0,
k 2 + k = 0, .. k 1= 0, k 2 = 1 Þ * = 1 + c 2 e x:
)
" + ' = 5 + 3
k 1= 0. :
2A + B = 3 Þ A = 5/2, B = 2.
,
y = c 1 + 2 x + 5 2/2 2
1. , .. : .- 8- ., .- .: , 2007.- 479., . 22.1
2. , .. . : . .- .: , 2012.- 208. 22.1
3. , .. . : . .- .: , 2012.- 416. 22.1
4. .. . . , . 2013. ISBN: 978-5-9061-7227-3
5. .. . . , . 2013. ISBN: 978-5-9061-7228-0
6. .. . . , . 2013. ISBN: 978-5-9061-7230-3
|
|
7. .. . . . 2012.
8. .. . . . 2012.
1. : / .. - .: , 2006, 2008, 2009.
2. : . ./ . .. -.:-,2004.
3. ( ): / . .. .: -, 2003.
4. . . . ., , 2004
: .
: , , .