dharr

Dr. David Harrington

948 Reputation

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15 years, 143 days
University of Victoria
Professor or university staff
Victoria, British Columbia, Canada

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I am a professor of chemistry at the University of Victoria, BC, Canada, where my research areas are electrochemistry and surface science. I have been a user of Maple since about 1990.

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These are replies submitted by dharr

@NaeemQau I don't have Maple 2019, so can't reproduce the error. But with the second set of parameters you don't see the error, so why not work from there and provide an approximate solution.

@NaeemQau At least in Maple 2017, the error is Error, (in dsolve/numeric/BVPSolve) initial Newton iteration is not converging. You should be able to find alpha with the extra boundary condition. I would back off on the accuracy conditions - Digits :=10 and a low abserr, and provide a simple initial guess (usually just the right general shape will do) using the appoxsoln option, based on what you think the solution looks like, When you can get some inaccurate solution, you can refine it.

@acer  Thanks. At the time I responded I could not see any other replies even though I refreshed the browser - this delay seems to be a random problem with Mapleprimes or perhaps my system.

Probably some parameter name doesn't have a value, but if you upload your worksheet with the green up arrow, someone can help you diagnose it.

@TeyhaNeedHelp Use * to enter multiplication, and give values to all parameters.

dsolve.mw

@Mohamed19 If you want something for general _k1, _k3, I don't think you'll get it, since any formula with an unspecified order of differentiation will be hard to deal with. If you use specific _k1,_k3, then you can evaluate and then convert. You can try the general case with convert.

I tried a few conversions, such as convert(  ,binomial) without success, but you could try some others.

@Adam Ledger In windows you can right-click on the .dll and choose properties. There is some information there, which may or may not have the authors etc; that depends on the .dll author.

@Mohamed19 I don't understand. Can you give an example of what you want as an answer.

@Mohamed19 It was unclear what your notation meant, and so I made a guess. Now it is unclear what form you want the answer in, so you will need to give more details of what you are looking for.

I answered this in the other thread https://www.mapleprimes.com/questions/228082-Derivative-Of-BesselJalpha-Sqrtu2v22uvcosphi but you want a sum form. You will need to specify the problem more clearly because your notation above is not clear and it is also not clear what form you really want.

@Mohamed19 I'm assuming the arguments are to be derivative of increasing order. Need to have fixed values of _k1 and _k3. Maybe something like:
 

q:=IncompleteBellB(_k1, _k3, %seq(diff(sqrt(u^2+v^2-2*u*v*cos(phi)), u$_j1),_j1 = 1 .. _k1-_k3+1));

IncompleteBellB(_k1, _k3, %seq(diff((u^2+v^2-2*u*v*cos(phi))^(1/2), [`$`(u, _j1)]), _j1 = 1 .. _k1-_k3+1))

eval(q,{_k1=4,_k3=2});
value(%);

IncompleteBellB(4, 2, %seq(diff((u^2+v^2-2*u*v*cos(phi))^(1/2), [`$`(u, _j1)]), _j1 = 1 .. 3))

-3*v^2*(cos(phi)^2-1)*(5*cos(phi)^2*v^2-8*u*v*cos(phi)+4*u^2-v^2)/(2*u*v*cos(phi)-u^2-v^2)^3

 


 

Download Bell.mw

@Zeineb I suggest you set up your conjecture as a Maple sum, and see if Maple can simplify to zero under the appropriate assumptions.

The code you copy-pasted earlier worked OK as I already showed. Now you have edited that out of your question and are asking something else that is not clear. Suggest you upload your worksheet - use the large green uparrow to load the worksheet with the problem and someone can take a look at it.

@mehdi jafari I agree that it is not in general, but it is if tau=0 and sqrt(sigma1^2) = sigma1, i.e., if sigma1 is positive, which is an important case. 

Suggest you upload your worksheet using the large green up-arrow. Then it will be easier for someone to diagnose.

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