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3:3:39 |
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0 , + II 3.3.29 | 3.3.31 , 3.3.25 .
( ) 2 3.3.292 3.3.31 +
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U x t = C1e pap x + C2epap x + |
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p3=2 |
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L1 "p 1 a2 # = ea2t:
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u2 x t = |
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3:3:42 |
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3 III 3.3.32 | 3.3.34 .
% 3.3.32 ,-% 3.3.34
d2U |
dU |
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a2 dx2 pU = 0 |
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U x t = C1e |
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3:3:43 |
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U x t = aM p |
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% %& . .
7, . *7.1, . 8 :
t
u x t = L 1 pM p U1 p = u10 t + Z u01 t d 3:3:44
0
u1 x t = L 1 U1 | t 1 |
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$ %! &' ( ! % ) *. !. 7, %!. ,7.2, . 13 . *
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3.3.44 ! " III 3.3.32 |3.3.34
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u3 x t = p |
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3=2 |
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3:3:45 |
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% ! &' " ( " 3.3.22 | 3.3.25 ' " & )3.3.35 , 3.3.39 , 3.3.42 3.3.45 .
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4.
, -
, Ox, -
- 2, 4, 5, 10|12%
@2u @ @u! ~
&x'S&x' @t2 = @x k&x'S&x'@x + S&x'f &x t' x 2 &0 l' t 0 &4:1'
x = 0 x = l
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u |
t=0 |
= g&x' x 2 |
0 l% |
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&4:2' |
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@u |
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= p&x' x 2 |
0 l%: |
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+ u&x t' | -
t , -
x, x | , &
t - . x + u&x t'', S&x' | , &x' | -
, & ' 0 | / , ~& ' |
k x f x t
0 . .
2 3 x = l &t' -
& 4 . ' |
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u x=l= &t' t 0: |
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2 x = l |
~&t' S&l' - |
& 6 ' |
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@u |
= &t' t 0 |
&4:4' |
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~&t' |
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k&l'S&l': |
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2 x = l -77 3 -
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& 8 '
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@x@u + hu! l= 0 t 0 |
4:5 |
h = |
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k l S l : |
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x = l , -~t
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x l= t t 0 |
4:6 |
t = h~t : |
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# , $%% & ' 4.1 ': |
x = const, S x = const, k x = const, |
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@2u |
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2 @2u |
4:7 |
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2 |
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2 + f x t |
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@t |
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@x |
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a2 = k, f x t = f~ x t :
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| 1 , | 0 ! |
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', f x t = |
f~ x t |
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~ |
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f x t | 0 ! 0- |
0 2 3 . |
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# |
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@2u2 |
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@2u2 + |
@2u2 |
1 + f x t |
4:8 |
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@t |
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@ |
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@y |
A |
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' ' ' u x y t 0, - |
0, 0 5 '. |
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6 5 ! ' |
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1 ' ! 0, 1- |
0, 0, 5 0 1 ' ' - ' '
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@2u |
2 |
4u + f7x t |
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4:9 |
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2 |
= a |
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@t |
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u7x t | & 1 |
v7 = grad u |
a2 = kp0 |
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0 |
k = |
Cp Cp | ! |
, Cv | - |
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Cv |
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! 59 , p0 0 | ' |
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229 |
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