desolve y'=(x+y)^2

05022015, 04:59 PM
Post: #21




RE: desolve y'=(x+y)^2
(05022015 04:45 PM)Tugdual Wrote: I have been able to achieve some results with Maxima and contrib_ode. well. ClassPad 400 can solve also Riccati equation? \[ y' + \frac{2x+1}{x}y  \frac{1}{x}y^{2} = x+2 \] thank you. ∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C  DM42, DM41X  WP34s Prime Soft. Lib 

05022015, 05:21 PM
(This post was last modified: 05022015 05:26 PM by Tugdual.)
Post: #22




RE: desolve y'=(x+y)^2
(05022015 04:59 PM)salvomic Wrote:Not 100% the same form as the solution you gave but quite close and definitely correct.(05022015 04:45 PM)Tugdual Wrote: I have been able to achieve some results with Maxima and contrib_ode. Off topic note: too bad this little evil doesn't have MES or unit of measuremernt like the 50g. 

05022015, 05:23 PM
Post: #23




RE: desolve y'=(x+y)^2
(05022015 05:21 PM)Tugdual Wrote: Not 100% the same form as the solution you gave but quite close and definitely correct. quite well ∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C  DM42, DM41X  WP34s Prime Soft. Lib 

05022015, 06:15 PM
Post: #24




RE: desolve y'=(x+y)^2
(05022015 12:49 PM)salvomic Wrote: EDIT:They are not the same Code:


05022015, 07:32 PM
(This post was last modified: 05022015 09:35 PM by salvomic.)
Post: #25




RE: desolve y'=(x+y)^2
(05022015 06:15 PM)parisse Wrote: They are not the same right! In about I get "xcas 1.1.419 (c) 200014, Bernard Parisse...", I presume it's the latest, however... If so, it's ok. ∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C  DM42, DM41X  WP34s Prime Soft. Lib 

05022015, 09:34 PM
Post: #26




RE: desolve y'=(x+y)^2
(05022015 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 ∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C  DM42, DM41X  WP34s Prime Soft. Lib 

05032015, 06:08 AM
Post: #27




RE: desolve y'=(x+y)^2
Without solution desolve(y'=(x+y)^2)
With particular solution (here a complex one) desolve(y'=(x+y)^2,x,y=x+i) 

05032015, 07:48 AM
(This post was last modified: 05032015 02:44 PM by salvomic.)
Post: #28




RE: desolve y'=(x+y)^2
(05032015 06:08 AM)parisse Wrote: Without solution desolve(y'=(x+y)^2) ok, but I must set something? I mean, also so, in XCas I get [] (see image) and no solution, always... ∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C  DM42, DM41X  WP34s Prime Soft. Lib 

05042015, 07:15 AM
Post: #29




RE: desolve y'=(x+y)^2
Check that version() returns 1.2.0. If not, you must install the unstable version.


05042015, 08:34 AM
(This post was last modified: 05112015 09:27 PM by salvomic.)
Post: #30




RE: desolve y'=(x+y)^2
(05042015 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 1.1.419 (c) 200014 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... ∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C  DM42, DM41X  WP34s Prime Soft. Lib 

05112015, 09:30 PM
Post: #31




RE: desolve y'=(x+y)^2
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 ∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C  DM42, DM41X  WP34s Prime Soft. Lib 

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