desolve y'=(x+y)^2 - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html) +--- Forum: HP Prime (/forum-5.html) +--- Thread: desolve y'=(x+y)^2 (/thread-3759.html) Pages: 1 2 RE: desolve y'=(x+y)^2 - salvomic - 05-02-2015 04:59 PM (05-02-2015 04:45 PM)Tugdual Wrote:  I have been able to achieve some results with Maxima and contrib_ode. But so far the ClassPad 400 is way above the rest and could successfully solve all equations. well. ClassPad 400 can solve also Riccati equation? $y' + \frac{2x+1}{x}y - \frac{1}{x}y^{2} = x+2$ thank you. RE: desolve y'=(x+y)^2 - Tugdual - 05-02-2015 05:21 PM (05-02-2015 04:59 PM)salvomic Wrote:   (05-02-2015 04:45 PM)Tugdual Wrote:  I have been able to achieve some results with Maxima and contrib_ode. But so far the ClassPad 400 is way above the rest and could successfully solve all equations. well. ClassPad 400 can solve also Riccati equation? $y' + \frac{2x+1}{x}y - \frac{1}{x}y^{2} = x+2$ thank you. Not 100% the same form as the solution you gave but quite close and definitely correct. Off topic note: too bad this little evil doesn't have MES or unit of measuremernt like the 50g. RE: desolve y'=(x+y)^2 - salvomic - 05-02-2015 05:23 PM (05-02-2015 05:21 PM)Tugdual Wrote:  Not 100% the same form as the solution you gave but quite close and definitely correct. quite well RE: desolve y'=(x+y)^2 - parisse - 05-02-2015 06:15 PM (05-02-2015 12:49 PM)salvomic Wrote:  EDIT: please, Parisse, help: I see two links: http://www-fourier.ujf-grenoble.fr/~parisse/giac/xcas_osx6_unstable.dmg.gz http://www-fourier.ujf-grenoble.fr/~parisse/giac/xcas_osx6.dmg.gz but that both here download the same (unstable) version... They are not the same Code:  -rw-r--r-- 1 parisse ensch 63880109 mars  27 12:38 xcas_osx6.dmg.gz -rw-r--r-- 1 parisse ensch 63972197 avril 28 13:32 xcas_osx6_unstable.dmg.gz Beware that the dmg name once opened by the disk mounter is the same. RE: desolve y'=(x+y)^2 - salvomic - 05-02-2015 07:32 PM (05-02-2015 06:15 PM)parisse Wrote:  They are not the same Code:  -rw-r--r-- 1 parisse ensch 63880109 mars  27 12:38 xcas_osx6.dmg.gz -rw-r--r-- 1 parisse ensch 63972197 avril 28 13:32 xcas_osx6_unstable.dmg.gz Beware that the dmg name once opened by the disk mounter is the same. right! In about I get "xcas 1.1.4-19 (c) 2000-14, Bernard Parisse...", I presume it's the latest, however... If so, it's ok. RE: desolve y'=(x+y)^2 - salvomic - 05-02-2015 09:34 PM (05-02-2015 05:30 AM)parisse Wrote:  Xcas can solve this equation. It is a Ricatti equation, you can solve it by giving a particular solution, otherwise the system rewrites it as a 2nd order equation. please, can you explain a practical example to try? thank you RE: desolve y'=(x+y)^2 - parisse - 05-03-2015 06:08 AM Without solution desolve(y'=(x+y)^2) With particular solution (here a complex one) desolve(y'=(x+y)^2,x,y=-x+i) RE: desolve y'=(x+y)^2 - salvomic - 05-03-2015 07:48 AM (05-03-2015 06:08 AM)parisse Wrote:  Without solution desolve(y'=(x+y)^2) With particular solution (here a complex one) desolve(y'=(x+y)^2,x,y=-x+i) ok, but I must set something? I mean, also so, in XCas I get [] (see image) and no solution, always... RE: desolve y'=(x+y)^2 - parisse - 05-04-2015 07:15 AM Check that version() returns 1.2.0. If not, you must install the unstable version. RE: desolve y'=(x+y)^2 - salvomic - 05-04-2015 08:34 AM (05-04-2015 07:15 AM)parisse Wrote:  Check that version() returns 1.2.0. If not, you must install the unstable version. as I noted above, I had xcas 1.1.4-19 (c) 2000-14 now I've installed 1.2 unstable and with the general equation I get $\frac{\mathrm{c\_1} \sin\left(x\right)-\mathrm{c\_2} \cos\left(x\right)-\mathrm{c\_1}\cdot x \cos\left(x\right)-\mathrm{c\_2}\cdot x \sin\left(x\right)}{\mathrm{c\_1} \cos\left(x\right)+\mathrm{c\_2} \sin\left(x\right)}$ then, with trigtan() -> $\frac{-\mathrm{c\_1}\cdot x+\mathrm{c\_1} \tan\left(x\right)-\mathrm{c\_2}\cdot x \tan\left(x\right)-\mathrm{c\_2}}{\mathrm{c\_1}+\mathrm{c\_2} \tan\left(x\right)}$ (trying your advise, $$\mathrm{desolve}\left(y'=(\left(x+y\right)^{2}),x,y=(-x+i)\right)$$ the result is $$[-x+i,\frac{4}{4\cdot \mathrm{c\_1} e^{-2*i\cdot x}+2*i}-x+i]$$) *** I tried also the Windows version, but the stable is still 1.1.4.19 also... RE: desolve y'=(x+y)^2 - salvomic - 05-11-2015 09:30 PM also with resolve(y'=-y^2,t,y) in the Prime I get [], while in the last XCas the correct answer is 1/(t+c_0) I hope they release soon a new firmware almost with the new XCas improvements :-) Salvo