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Author Comment/Response
jf
04/20/13 8:47pm

a) Is f already defined somewhere in your code?
Clear[f]
before running these inputs would eliminate that possibility.

b) DSolve needs both independent variables in the third argument.

c) DiracDelta is not a nice function. It would not surprise me if DSolve cannot do much with it.

d) That these just echo says DSolve did not know how to solve them.

In[1]:= eqns = {Derivative[0, 1][f][x, t] == a*Derivative[2, 0][f][x, t],
Derivative[1, 0][f][0, t] == 0, Derivative[1, 0][f][L, t] == 0,
f[x, 0] == DiracDelta[x]}


In[2]:= DSolve[eqns, f[x, t], {x, t}]

Out[2]=
DSolve[{f^(0,1)[x, t] == a f^(2,0)[x, t], f^(1,0)[0, t] == 0, f^(1,0)[L, t] == 0, f[x, 0] == DiracDelta[x]},
f[x, t], {x, t}]

In[3]:= DSolve[eqns, f, {x, t}]

Out[3]=
DSolve[{f^(0,1)[x, t] == a f^(2,0)[x, t], f^(1,0)[0, t] == 0, f^(1,0)[L, t] == 0, f[x, 0] == DiracDelta[x]},
f, {x, t}]


In[4]:= $Version

Out[4]= 9.0 for Microsoft Windows (64-bit) (January 25, 2013)




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Subject (listing for 'BC keeps returning true')
Author Date Posted
BC keeps returning true darin 04/20/13 10:49am
Re: BC keeps returning true jf 04/20/13 8:47pm
Re: Re: BC keeps returning true darin 04/21/13 06:50am
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