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#26 Re: Help Me ! » Regular expression » 2013-12-16 09:29:50
Hi evinda
Am getting a DFA with 5 states.
I tried to draw a DFA and I also got one with 5 states!!!!
#27 Re: Help Me ! » Regular expression » 2013-12-16 07:30:50
Hi;
I know what a regular expression is but I have no idea how to use it with cellular automata.
Have you tried the Stack Exchange or Stack Overflow?
I found similar questions with helpful answers there!Thanks for the hint 
#28 Help Me ! » Regular expression » 2013-12-14 22:12:22
- evinda
- Replies: 15
Hi!!
R=
I have this regular expession and have to draw the DFA..But I haven't understood which language is meant..Could you give me a hint? 
#29 Re: Help Me ! » Wronskian use identities ! » 2013-12-13 11:18:19
That is what I am saying. If there is only one solution. Is there another solution?
There should be..because v1 and v2 are linearly independent
#30 Re: Help Me ! » Wronskian use identities ! » 2013-12-13 09:37:07
Of course you do, but you already got the solution to DE earlier.
But then don't we find that v1(x)=v2(x) ? Or not? I haven't understood...
#31 Re: Help Me ! » Wronskian use identities ! » 2013-12-12 08:37:03
That is true but have you used the solutions to compute the wronskian?
Can't I just write that the Wronskian is equal to:
| v_{1}(0) (v_{1}(0))' |
| v_{2}(0) (v_{2}(0))' |
Do you mean that I have to solve the differential equation that is given for
and ?#32 Re: Help Me ! » Wronskian use identities ! » 2013-12-12 07:57:13
How do you know the two solutions are linearly independent?
Because the exercise says that v1,v2 are solutions of the differential equation so that
is not constant..So,.So, ...
#33 Re: Help Me ! » Wronskian use identities ! » 2013-12-12 06:48:00
I do not know why it should be non zero.
Did you compute the Wronskian?
Because there is a theorem that says that if two solutions of a differential equation are linearly independent,their Wronskian is nonzero!!!
#34 Re: Help Me ! » Wronskian use identities ! » 2013-12-12 06:40:43
But the Wronkian should be nonzero..So,what do I have to do??
#35 Re: Help Me ! » Wronskian use identities ! » 2013-12-12 02:00:19
What do you get for v1(x) and v2(x)?
I haven't found them..how could I do this?
#36 Re: Help Me ! » Wronskian use identities ! » 2013-12-12 01:45:13
What did you get for
(v1(0)v2'(0)-v2(0)v1'(0))?
How can I find this value?
#37 Re: Help Me ! » Wronskian use identities ! » 2013-12-12 01:23:26
Do you mean that I have to use
? I tried and got W(x)=(v1(0)v2'(0)-v2(0)v1'(0))*e^(-ax).Is it right so far?and how can I continue?#38 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 11:21:16
Yes, but first you need to find the Wronskian. You can do this using Abel's identity.
Do we have a
we could use?#39 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 10:43:29
Well, the point of finding the determinant is to show that there are solutions, so, yes, you can. Of course, you should treat d1 and d2 as the unknowns when finding the determinant.
So,I find the determinant and notice that it equals to the Wronskian,so it is
.And then?#40 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 10:37:32
Find the determinant of the system of equations given in the second to last line of your post 1. You will see that it actually represents the Wronskian at x=0.
Don't you mean these two:
, d_{1}{v_{1}}'(0)+d_{2}{v_{2}}'(0)={f}'(0) ?Can I find the determinant,although I haven't shown that there and that satisfy these conditions??
#41 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 10:29:57
Hi evinde
For the first part, use the fact that the Wronskian is non-zero and the fact that the determinant of the system of equations is the Wronskian at x=0.
How can I use these facts??I haven't understood yet... 
#42 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 10:28:46
Why is the Wronskian non - zero?
Also,because of the fact that the solutions are linearly independent!!!
#43 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 10:24:04
That makes v1(x) = v2(x) which makes the determinant 0 that means they are linearly dependent.
Seems nonsensical.
So,what have I done wrong?? Is there an other way to do this?
#44 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 10:21:03
And how can I continue now??
#45 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 10:17:13
Should not you have use the roots rather than the discriminant?
Where do you mean?At the general solution?
#46 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 10:15:22
Hi evinda
Those are the solutions, but I don't think you are supposed to use them.
But???How else can I start???
#47 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 10:13:43
I am not getting that as a solution to the DE. Where is c1 and c2 in your solution?
Did you copy the question correctly?
Yes,I copied the question correcty..Should I have used
and instead of c_{1} and ?
#48 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 10:08:36
I found the Characteristic equation,that is
that has discriminant withSo,
Am I right so far?And how can I continue?
#49 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 09:53:52
That yields a Wronskian of
Now what?
I haven't understood..Do you mean that I have to take the derivative of the Wronskian and solve the DE or which DE do you mean?? 
#50 Re: Help Me ! » Wronskian use identities ! » 2013-12-11 09:45:01
That would require solving the DE. Since when do you need the solve the DE to get the Wronskian?
Which DE do you mean that I have to solve??