Assuming that the "if" clause is as in your later post and that you used the proper inequality symbols, Maple is telling you that it does not know the value of n2[1]. Your code doesn't assign it a value, so there's some code missing. There are also three incorrect lines of code before list2 := 'list2': I am surprised that Maple did not report these errors. Hope this helps. J. Tarr

Try something like this, restart; ic := {x(0)=1,y(0)=1}; sys := {diff(x(t),t)=x(t)+y(t),diff(y(t),t)=x(t)+y(t)}; soln := dsolve(sys union ic); assign(soln); seq( evalf(eval(x(t),t=i)) ,i=1..10); Copy the output from the last line and paste it into a cell in Excel. Select the cell in Excel, choose Data > Text to Columns > Delimited > Next > Comma > Next > General (or whatever format you wish) > Finish. Since x(t) and y(t) are identical, the latter can be obtained by copying in Excel. Hope this helps. J. Tarr

Try something like this, restart; ic := {x(0)=1,y(0)=1}; sys := {diff(x(t),t)=x(t)+y(t),diff(y(t),t)=x(t)+y(t)}; soln := dsolve(sys union ic); assign(soln); seq( evalf(eval(x(t),t=i)) ,i=1..10); Copy the output from the last line and paste it into a cell in Excel. Select the cell in Excel, choose Data > Text to Columns > Delimited > Next > Comma > Next > General (or whatever format you wish) > Finish. Since x(t) and y(t) are identical, the latter can be obtained by copying in Excel. Hope this helps. J. Tarr

This is a copy of your worksheet incorporating my suggestion. I hope it helps solve your problem. View 724_PDE.mw on MapleNET or Download 724_PDE.mw Good luck, J. Tarr

This is a copy of your worksheet incorporating my suggestion. I hope it helps solve your problem. View 724_PDE.mw on MapleNET or Download 724_PDE.mw Good luck, J. Tarr

If you want an implicit plot of "i" and "PP", try this: restart; #with(LinearAlgebra): # IMPACT OF A FLUID FILLED SPHERICAL SHELL ("NON-HERTZIAN") WITH A "HERTZIAN" BALL- # All SI units metric # Input Parameters fluid filled spherical shell Rsh:=0.0725: # radius brain h:=0.00561: # thickness skull Esh:=1.6e9: # Young's modulus skull mush:=0.3: # Poisson's ratio skull vsh:=0: # velocity of head msh:=1.96: # mass of head ksh:=evalf(2.3*Esh*h^2/(Rsh*(1-mush^2)^(1/2))): # ovalstiff # Input Parameters for hertzian ball mub:=0.25: # Poisson's ratio ball Eb:=207e9: # Young's modulus ball Rb:=0.009: # Radius curvature ball vb:=1.98: # Velocity of ball mb:=0.045*i: m:=1/(1/msh+1/mb): R:=1/(1/(Rsh+h)+1/Rb): Ep:=Esh*Eb/((1-mush^2)*Esh+(1-mub^2)*Eb): v:=abs(vsh-vb): kb:=4/3*R^(1/2)*Ep: alpha:=4/5*ksh/kb^(2/3): beta:=ksh*m*v^2: eq:=PP+alpha*PP^(5/6)-beta; plots[implicitplot](eq=0,i=0..500,PP=0..10^7); Hope this helps. J. Tarr

Glad to see that you have solved your problem. As a matter of interest where does the variable y033 acquire its value? It doesn't appear in the worksheet that you posted above until it appears in the while expression. J. Tarr

It looks as though the while expression is missing an arithmetic operator, e.g. A<=y*0.33. Hope this helps J. Tarr

If you are looking for examples on optimization, there is a sample worksheet included with Maple 10 - see ?Optimization. You could also take a look at the Maple Applications Center and at this Hope this helps. J. Tarr

See Maple Applications Center J. Tarr

See Maple Applications Center J. Tarr

I had no problems with subs, or eval (which is better usage), in the solution to your ODE, provided that I did not use equation labels to reference the ODE and ICs. Using labels, your problem appeared. You might care to send a bug report to Maplesoft. A second point that you could consider, is that it is often better to use "assuming" when solving ODEs instead of "assume". It applies only to the command with which it is associated and assumptions are not left on the variables. Good luck, J. Tarr

I had no problems with subs, or eval (which is better usage), in the solution to your ODE, provided that I did not use equation labels to reference the ODE and ICs. Using labels, your problem appeared. You might care to send a bug report to Maplesoft. A second point that you could consider, is that it is often better to use "assuming" when solving ODEs instead of "assume". It applies only to the command with which it is associated and assumptions are not left on the variables. Good luck, J. Tarr

I am afraid that this does not produce a solution to the ODE: it merely restates the original in a different form. Thomas Richard showed how to solve this ODE using one of dsolve's numerical solvers in an earlier answer to this question. See ?dsolve,numeric. Perhaps the following will help. J. Tarr View 724_Solution of 2nd Order ODE.mw on MapleNET or Download 724_Solution of 2nd Order ODE.mw

Maple 10.03 on my Windows box has 27 palettes! In addition to those Joe listed, there are Components, Cyrillic, Diacritical Marks, Roman Extended (upper case), Roman Extended (lower case), Accents, Constants & Symbols, and Punctuation. Might be a slight case of overkill… Hope this helps, J. Tarr