b*****y
发帖数: 163 | 1 try matlab symbolic toolbox:
y=dsolve('D2y=a*exp(4*y)+b'); |
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b*****y
发帖数: 163 | 2 The following is the full turn-out in matlab 6.0:
>> y=dsolve('D2y=a*exp(4*y)+b')
Warning: Explicit solution could not be found; implicit solution returned.
> In /usr/local/matlab6/toolbox/symbolic/dsolve.m at line 292
y =
[ 2*Int(1/(2*a*exp(4*a)+8*b*a+4*C1)^(1/2),a=``..y)-t-C2=0,
-2*Int(1/(2*a*exp(4*a)+8*b*a+4*C1)^(1/2),a=``..y)-t-C2=0]
>> pretty(y)
[ y
[ /
[ | 1
[2 | -------------------------------- da - t - C2 = 0 ,
[ | |
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d***n
发帖数: 3 | 3 这个二元非线性微分方程：
d2y/du2 = k*exp(u)/sqrt(y)
边界条件已知：y(0) = 0 ; y(u1)=b;
其中：k, u1, b 都是常数。
多谢！ |
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z*******u
发帖数: 41 | 4 y=f(x)
y"=y[a+b/(c+y)], 其中a,b,c是常数。y" is d2y/dx2,二阶导数。
谢谢 |
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