Dr. David Harrington

3110 Reputation

17 Badges

17 years, 345 days
University of Victoria
Professor or university staff
Victoria, British Columbia, Canada

Social Networks and Content at Maplesoft.com

Maple Application Center
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.

MaplePrimes Activity

These are replies submitted by dharr

@Jjjones98 invfourier(expr, w , t) doesn't make sense if expr contains t; you would be going from the time domain to the time domain.

@Jjjones98 So invfourier cannot evaluate it, without more information, perhaps specifying values of some constants. Working with any expression that has general roots of a quartic polynomial will be almost impossible. But something is very strange since you inverse laplaced into the time demain and then inverse Fourier from an expression with t in it, into another time domain. ??

@Jjjones98 This is the same file as the original.

@Jjjones98 yes, there is invfourier. See ?inttrans for help on the different forward and inverse transforms.

@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.


@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))


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




Download Bell.mw

First 14 15 16 17 18 19 20 Last Page 16 of 29