awass

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These are questions asked by awass

nans:=dsolve({(-y^4+y^2)*diff(U(y),y,y)+(-2*y^2+14.2)*diff(U(y),y)*y-15.2*U(y)*(U(y)-1)*(U(y)+1) = 0, DU(.99999) = -.3401375821,U(.99999)= 0.3000034013},numeric);
Error, (in dsolve/numeric/process_input) invalid specification of initial conditions, got DU(.99999) = -.3401375821

I have an ode y''(x) + ...=0 that depends on a parameter a and I would like to see how the solutions vary with a. I created a procedure using odeplot to yield a sequence of plots and display them. Not bad but I really need to look more closely. Plotting y for a=7 and overlaying a plot for y=7.1 is too crude. I want to look at y(x,7.1) - y (x,7) or y(x,7.1) /y (x,7) for x=0..3 say. The obvious solution is to compute y(x,7.1) for x=0..3 and save it as a vector and also y(x, 7). How can I do that so that the pointsx at which y(x, 7.1) are the same as the pointsx for which y(x,7) are evaluated. In other words, how can I specify to dsolve the intermediate points xj for which y(x) is calculated? 

I am starting a new project and I anticipate creating dozens of files along the way. Each file will need the same collection of definitions, procedures, etc. and I would prefer not to have to copy and pace them as a preamble each time I open anew file. I guess I could write some startup code but would that mean every time I open an unrelated Maple file the Startup code would be laoded? I will be using Maple for other things besides this project. Also, while the stratup code would be hidden most of the time I would perhaps like to be able to see what the n1 procedure is; n1(x) would invoke the procedure-I just want to see waht it does. I usually endup up labeling my files in some lazy way so if I want to go back and find something it takes for ever. Any suggestions for improving that?

Thanks,

I tried the following procedure in a worksheet; Maple did not like it and claimed there was an error. However, I cannot even copy this to a Maple prompt; it jumps to another type of region. Any ideas? If I retype the command there is no problem with an error.

It reminds me of Maple 2 and the letter t which sometimes had to be retyped to get Maple to respond-a very strange bug which was eliminated years ago.

I occasionally find myself inexplicably in a region of my worksheet that does not respond to my editing, fe.g., I cannot erae or I cannot copy. I recently typed a command-there was an error of some form and I tried unsuccessfully to edit it. Then I tried to copy the code and enter it at a prompt. It refused to enter it at the prompt but copied it below the prompt in a strnge region that I do not understand. When I retyped the command at a prompt it worked fine. I do not understand th dead regions that pop up mysteriously. (I am using Maple 2024 on a Mac) The page is too long to copy but I could upload it if given directions.

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