Problem with differential equation (DESOLVE)

03032015, 05:29 PM
Post: #1




Problem with differential equation (DESOLVE)
Hello,
I don't know why when I try to solve a Homogeneous differential equation my hp prime I get something like: desolve((y') = ((y/x)+(x/y)),y) = [pnt[G_0*e^((1/2)*_(t38)^2),G_0*_(t38)*e^((1/2)*_(t38)^2)]] the solution must be Y^2=X^2*LN(X^2)+C*X^2 anyone can help me? please. 

03032015, 06:59 PM
(This post was last modified: 03032015 07:12 PM by salvomic.)
Post: #2




RE: Problem with differential equation (DESOLVE)
(03032015 05:29 PM)ZellAllon Wrote: Hello, see here: Parisse replied to me few time ago... the "strange" expression should be like \[ y=c*e^{\frac{t^{2}}{2}} \ AND \ y=c*t*e^{\frac{t^{2}}{2}} \] G_0 ok for "c", but, yes, "_t38" is a bit bizzarre, and we are lucky that it is not "p38" Note also that \( e^{\frac{t^{2}}{2}} \) is simply \( \sqrt{e^{t^{2}}} \) ... ∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C  DM42, DM41X  WP34s Prime Soft. Lib 

03042015, 10:07 AM
Post: #3




RE: Problem with differential equation (DESOLVE)
You get parametric solutions currently. With Xcas current CAS version, you would get
[√2*x*√(ln(x/G_0)),√2*x*√(ln(x/G_0))] 

03042015, 04:49 PM
Post: #4




RE: Problem with differential equation (DESOLVE)
(03032015 06:59 PM)salvomic Wrote:ok, understood, thanks.But how can I take these parametric solutions and get y as a function of x?(03032015 05:29 PM)ZellAllon Wrote: Hello, 

03042015, 05:44 PM
Post: #5




RE: Problem with differential equation (DESOLVE)  
03042015, 06:09 PM
Post: #6




RE: Problem with differential equation (DESOLVE)
(03042015 05:44 PM)ZellAllon Wrote: How do you get that solution? explain to me please! That is the author of the CAS inside Prime. He is using the pc version (which is newer then the current version in Prime) and that result is returned. If/Until that code is put into the Prime firmware the calculator will continue to return the result you posted. TW Although I work for HP, the views and opinions I post here are my own. 

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