Re: [sage-support] Solving 4th order differential equation
Maybe (I don‘t have my pc on me right now) the “de = L*E*diff(y,x,2)==q“ is
making some problems because that is also a comparing method (and so, de is
True or False)
El 29/05/2012 07:29, "Priyanka Kapoor"
escribió:
> Thanks for helping. I used a mathematical approach for 4th order
> derivative i.e substituing double derivative as a variable, solving
> for 2nd order differential equation and substituting back and again
> solved for 2nd order differentiation.
> here is code:
> var('w,x,E,L,k1,k2')
> y = function('y', x)
> w= function('w' , x)
> q = function('q', x)
> assume(L>0)
> assume(E>0)
> q=x
> de=E*L*diff(y,x,2)==q
> y_res=desolve(de,y,ivar=x,ics=[L,0,0])
> des=diff(w,x,x)-y_res==0
> dess=desolve(des,w,ivar=x,ics=[0,0,0])
> print "Solution of bernoulli's equation:",dess
> #Remeber plot can't be formed without giving values of
> constant###
> E=6
> L=10
> p=plot( 1/120*(20*L^3*x^2 - 10*L^2*x^3 + x^5)/(E*L),(x,0,1),thickness=3)
> p.show()
>
>
>
>
>
> --
> Priyanka Kapoor
> priyankacool10.wordpress.com
> Linux User Group, Ludhiana
>
> --
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Re: [sage-support] Solving 4th order differential equation
Thanks for helping. I used a mathematical approach for 4th order
derivative i.e substituing double derivative as a variable, solving
for 2nd order differential equation and substituting back and again
solved for 2nd order differentiation.
here is code:
var('w,x,E,L,k1,k2')
y = function('y', x)
w= function('w' , x)
q = function('q', x)
assume(L>0)
assume(E>0)
q=x
de=E*L*diff(y,x,2)==q
y_res=desolve(de,y,ivar=x,ics=[L,0,0])
des=diff(w,x,x)-y_res==0
dess=desolve(des,w,ivar=x,ics=[0,0,0])
print "Solution of bernoulli's equation:",dess
#Remeber plot can't be formed without giving values of
constant###
E=6
L=10
p=plot( 1/120*(20*L^3*x^2 - 10*L^2*x^3 + x^5)/(E*L),(x,0,1),thickness=3)
p.show()
--
Priyanka Kapoor
priyankacool10.wordpress.com
Linux User Group, Ludhiana
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Re: [sage-support] Solving 4th order differential equation
On Fri, May 25, 2012 at 5:51 AM, Priyanka Kapoor wrote: > On Fri, May 25, 2012 at 3:06 PM, David Joyner wrote: >> Did you try sympy? > > No. Does it solve 4th order diff. eq.? If yes, can you please give > link. And approach that i am using is wrong or invalid? > I googled "sympy differential equation" and got this: http://docs.sympy.org/dev/modules/mpmath/calculus/odes.html There might be better links. I just mentioned sympy because AFAIK it solved more DEs that Sage's default system (which as you point out is currently maxima). I'm not sure if it will work, just a suggestion. I'm not sure what is wrong with your code either. It seems your traceback message tells you that though. > > > -- > Priyanka Kapoor > priyankacool10.wordpress.com > Linux User Group, Ludhiana > > -- > To post to this group, send email to sage-support@googlegroups.com > To unsubscribe from this group, send email to > sage-support+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/sage-support > URL: http://www.sagemath.org -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
Re: [sage-support] Solving 4th order differential equation
On Fri, May 25, 2012 at 3:06 PM, David Joyner wrote: > Did you try sympy? No. Does it solve 4th order diff. eq.? If yes, can you please give link. And approach that i am using is wrong or invalid? -- Priyanka Kapoor priyankacool10.wordpress.com Linux User Group, Ludhiana -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
Re: [sage-support] Solving 4th order differential equation
Did you try sympy?
On Friday, May 25, 2012, Priyanka Kapoor wrote:
> I want to know how to solve fourth order differential equation in
> sagemath. Question which i actually want to solve is Euler-bernoulli
> equation.
>http://en.wikipedia.org/wiki/Euler%E2%80%93Bernoulli_beam_theory
> I searched a lot about solving this, but didn't succeed. Does anyone
> know how to solve this equation. Whether this equation is solved in
> parts by taking second order derivative two times or directly.
> Please give any link that shows wonderful working of sagemath
> regarding 4th order differential equation. I tried this:
>
> var('k1,k2')
> y=function('y',x)
> w=function('w',x)
> q=function('q',x)
> var('x')
> de=diff(y,x,x)==q ##here i put (d^2/dx^2)(w)=y , thus (d^4/dx^4)(w)=
> (d^2/dx^2)(y)
> res=desolve(de,dvar=y,ivar=x)
> e=diff(w,x,x)-res==0
> res1=desolve(res,dvar=w,ivar=x,contrib_ode=True) ## As solution of
> above will give y and again i put y= (d^2/dx^2)(w) i.e substitute back
> print res1
> print res
>
> NotImplementedError: Maxima was unable to solve this ODE.
>
> Please help.
>
>
>
>
> --
> Priyanka Kapoor
> priyankacool10.wordpress.com
> Linux User Group, Ludhiana
>
> --
> To post to this group, send email to
> sage-support@googlegroups.com
> To unsubscribe from this group, send email to
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> URL: http://www.sagemath.org
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