I am trying to work with differential equations and found this:
It appears the integrate function can only integrate dy/dt back to y but not d2 y/dy2 back to dy/dt.
Matt
Bug or my mistake?
Modérateur : xcasadmin
Re: Bug or my mistake?
Also, it doesn't integrate dy/dt back to y if it is entered as
diff(y(t),t).
If you enter
eq1 := diff(y(t),t,1)
then again
int(eq1,t)
returns undef.
Oddly, perhaps,
diff(y(t),t,1)
returns
diff(y(t),t,1)
I expected
diff(y(t),t)
Jay
diff(y(t),t).
If you enter
eq1 := diff(y(t),t,1)
then again
int(eq1,t)
returns undef.
Oddly, perhaps,
diff(y(t),t,1)
returns
diff(y(t),t,1)
I expected
diff(y(t),t)
Jay
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- Messages : 146
- Inscription : mer. janv. 13, 2010 3:20 pm
Re: Bug or my mistake?
It appears that any diff command with 3 arguments won't integrate back. int(diff(y(t),t),t) seems to work for me.
cygwin xcas
xcas 1.9.0-29 (c) 2000-18
Win 10 22H2
cygwin xcas
xcas 1.9.0-29 (c) 2000-18
Win 10 22H2
Re: Bug or my mistake?
Well, Xcas is not really implemented for solving these kinds of integrals, it expects defined symbolic argument. I'm able to fix these simple examples, but integration by part for example will not work.
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- Messages : 146
- Inscription : mer. janv. 13, 2010 3:20 pm
Re: Bug or my mistake?
Fixing these simple examples would help me a lot.
Matt
Matt
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- Messages : 146
- Inscription : mer. janv. 13, 2010 3:20 pm
Re: Bug or my mistake?
Thank you, works great now.