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Topic: dsolve
Replies: 2   Last Post: Jun 13, 2013 11:13 AM

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Alan Weiss

Posts: 1,267
Registered: 11/27/08
Re: dsolve
Posted: Jun 13, 2013 9:10 AM
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On 6/13/2013 8:51 AM, Helmut wrote:
> In Shampine et al. "Solving ODEs with MATLAB" (2003), p. 18, Exercise
> 1.1, an example from MATLAB (2000) "help dsolve" is cited:
>

>>> Y = dsolve('(Dy)^2 + y^2 = 1', y(0) = 0')
>
> with the correct solution
>
> Y = [ sin(t) ]
> [ -sin(t) ]
>
> Now, with Matlab 2012a student, for an identical input I get the solution
>
> Y =
> cosh((pi*i)/2 + t*i)
> cosh((pi*i)/2 - t*i)
>
> which seems to me to be wrong.
>
> What should I do?
> Helmut
>
>


After getting this seemingly odd answer, try the following:

z = simplify(Y)

z =

-sin(t)
sin(t)

Alan Weiss
MATLAB mathematical toolbox documentation


Date Subject Author
6/13/13
Read dsolve
Helmut
6/13/13
Read Re: dsolve
Alan Weiss
6/13/13
Read Re: dsolve
Helmut

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