## [Maxima-bugs] [ maxima-Bugs-1567383 ] initial value problem gives rise to error

 [Maxima-bugs] [ maxima-Bugs-1567383 ] initial value problem gives rise to error From: SourceForge.net - 2006-12-26 21:54:22 ```Bugs item #1567383, was opened at 2006-09-28 17:38 Message generated for change (Comment added) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1567383&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. >Category: Lisp Core - Differential eqns Group: None >Status: Closed >Resolution: Invalid Priority: 5 Private: No Submitted By: Pedro Tytgat (pedrotytgat) Assigned to: Nobody/Anonymous (nobody) Summary: initial value problem gives rise to error Initial Comment: (%i1) 'diff(y,x)+2*y=3; (%o1) 'diff(y,x,1)+2*y=3 (%i2) ic1(%, x=0, y=1); Attempt to differentiate with respect to a number: 0 #0: ic1(soln='diff(y,x,1)+2*y = 3,xc=x = 0,yc=y = 1)(ode2.mac line 300) #1: ic1(?_l=['diff(y,x,1)+2*y = 3,x = 0,y = 1]) -- an error. Quitting. To debug this try debugmode(true); The problem does have a solution, though: (%i3) ode2(%o1, y, x); (%o3) y=%e^(-2*x)*((3*%e^(2*x))/2+%c) (%i4) subst(0, x, %); (%o4) y=%c+3/2 (%i5) subst(1, y, %); (%o5) 1=%c+3/2 (%i6) solve([%], [%c]); (%o6) [%c=-1/2] ---------------------------------------------------------------------- >Comment By: Robert Dodier (robert_dodier) Date: 2006-12-26 14:54 Message: Logged In: YES user_id=501686 Originator: NO Pedro, thanks for your interest in Maxima and thanks for submitting the bug report. ic1 (and also ic2 and bc2) is supposed to be called after ode2 finds a solution. ic1 itself does not find the solution. So it works like this: (%i2) 'diff(y, x) + 2*y = 3; (%o2) 'diff(y,x,1)+2*y = 3 (%i3) ode2(%, y, x); (%o3) y = %e^-(2*x)*(3*%e^(2*x)/2+%c) (%i4) ic1(%, x=0, y=1); (%o4) y = %e^-(2*x)*(3*%e^(2*x)-1)/2 Certainly, the documentation should be clearer. Closing this report as invalid (not a bug). ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1567383&group_id=4933 ```

 [Maxima-bugs] [ maxima-Bugs-1567383 ] initial value problem gives rise to error From: SourceForge.net - 2006-09-28 23:38:42 ```Bugs item #1567383, was opened at 2006-09-29 01:38 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1567383&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core - Solving equations Group: None Status: Open Resolution: None Priority: 5 Submitted By: Pedro Tytgat (pedrotytgat) Assigned to: Nobody/Anonymous (nobody) Summary: initial value problem gives rise to error Initial Comment: (%i1) 'diff(y,x)+2*y=3; (%o1) 'diff(y,x,1)+2*y=3 (%i2) ic1(%, x=0, y=1); Attempt to differentiate with respect to a number: 0 #0: ic1(soln='diff(y,x,1)+2*y = 3,xc=x = 0,yc=y = 1)(ode2.mac line 300) #1: ic1(?_l=['diff(y,x,1)+2*y = 3,x = 0,y = 1]) -- an error. Quitting. To debug this try debugmode(true); The problem does have a solution, though: (%i3) ode2(%o1, y, x); (%o3) y=%e^(-2*x)*((3*%e^(2*x))/2+%c) (%i4) subst(0, x, %); (%o4) y=%c+3/2 (%i5) subst(1, y, %); (%o5) 1=%c+3/2 (%i6) solve([%], [%c]); (%o6) [%c=-1/2] ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1567383&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-1567383 ] initial value problem gives rise to error From: SourceForge.net - 2006-12-26 21:54:22 ```Bugs item #1567383, was opened at 2006-09-28 17:38 Message generated for change (Comment added) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1567383&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. >Category: Lisp Core - Differential eqns Group: None >Status: Closed >Resolution: Invalid Priority: 5 Private: No Submitted By: Pedro Tytgat (pedrotytgat) Assigned to: Nobody/Anonymous (nobody) Summary: initial value problem gives rise to error Initial Comment: (%i1) 'diff(y,x)+2*y=3; (%o1) 'diff(y,x,1)+2*y=3 (%i2) ic1(%, x=0, y=1); Attempt to differentiate with respect to a number: 0 #0: ic1(soln='diff(y,x,1)+2*y = 3,xc=x = 0,yc=y = 1)(ode2.mac line 300) #1: ic1(?_l=['diff(y,x,1)+2*y = 3,x = 0,y = 1]) -- an error. Quitting. To debug this try debugmode(true); The problem does have a solution, though: (%i3) ode2(%o1, y, x); (%o3) y=%e^(-2*x)*((3*%e^(2*x))/2+%c) (%i4) subst(0, x, %); (%o4) y=%c+3/2 (%i5) subst(1, y, %); (%o5) 1=%c+3/2 (%i6) solve([%], [%c]); (%o6) [%c=-1/2] ---------------------------------------------------------------------- >Comment By: Robert Dodier (robert_dodier) Date: 2006-12-26 14:54 Message: Logged In: YES user_id=501686 Originator: NO Pedro, thanks for your interest in Maxima and thanks for submitting the bug report. ic1 (and also ic2 and bc2) is supposed to be called after ode2 finds a solution. ic1 itself does not find the solution. So it works like this: (%i2) 'diff(y, x) + 2*y = 3; (%o2) 'diff(y,x,1)+2*y = 3 (%i3) ode2(%, y, x); (%o3) y = %e^-(2*x)*(3*%e^(2*x)/2+%c) (%i4) ic1(%, x=0, y=1); (%o4) y = %e^-(2*x)*(3*%e^(2*x)-1)/2 Certainly, the documentation should be clearer. Closing this report as invalid (not a bug). ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1567383&group_id=4933 ```

No, thanks