meta user
network profile
| bio | website | stephenluttrell.com |
|---|---|---|
| location | West Malvern, United Kingdom | |
| age | ||
| visits | member for | 11 months |
| seen | 12 hours ago | |
| stats | profile views | 58 |
I have been a Mathematica user since 1981, using version 0 to do QCD calculations for my PhD, and all subsequent versions to do research into various sorts of adaptive information processing. The use of Mathematica has been the key to almost every new result that I have discovered, because I can do "experiments" at the speed at which I think (more or less), so I don't get bored or lose my train of thought. Mathematica and I are a well-matched symbiotic pair!
|
May 4 |
awarded | Enlightened |
|
May 4 |
awarded | Nice Answer |
|
Mar 31 |
comment |
How can I factor my trigonometric equation?TrigFactor[3 Sin[x]^2 - 3 Cos[x] - 6 Sin[x] + 2 Sin[2 x] + 3] gives the output -2 Sqrt[2]
Sin[\[Pi]/4 - x/2] (Cos[x/2] - 3 Sin[x/2]) (2 Cos[x/2] -
Sin[x/2]) Sin[x/2]. This has an overall factor Sin[x/2] which gives your x = 0 solution. |
|
Mar 27 |
awarded | Fanatic |
|
Mar 22 |
comment |
creating an API or Widget based on a Mathematica notebook To create a CDF that is embedded into a web page you could use (Mma version 9) the File / CDF Export / Web Embeddable... menu item. The online documentation is here. |
|
Mar 11 |
comment |
Why is FindRoot initial value far from the specified one? You could constrain the search range using FindRoot[lhs==rhs,{x,Subscript[x, start],Subscript[x, min],Subscript[x, max]}] searches for a solution, stopping the search if x ever gets outside the range Subscript[x, min] to Subscript[x, max]. |
|
Feb 22 |
comment |
How to calculate partial derivative of an unknown function Good point. Why should Dt differentiate correctly w.r.t. f[x,y] but not w.r.t. Plus[x,y]? Anyway, the original question - i.e. the partial derivative of a function u[x,y] w.r.t. f[x, y] - is answered by Dt[u[x, y], f[x, y]]. |
|
Feb 21 |
answered | How to calculate partial derivative of an unknown function |
|
Feb 17 |
comment |
Reproducing the Integral Definition of the Modified Bessel function I think it's because Mathematica can successfully verify that this integral is correct - i.e. can work backwards when you give it the result in advance - but can't work forwards to arrive at the result when it is unknown in advance. |
|
Feb 16 |
comment |
Reproducing the Integral Definition of the Modified Bessel function If you actually set m to be an integer, then the integral evaluates to give an expression in terms of BesselI[1,z] and BesselI[2,z] - I tried a few cases and they all came out this way. Then if you equate this result to the expected result Pi BesselI[m,z] (with m set the same as above) and then FullSimplify you get True. Although this doesn't solve your problem, you might find it useful. |
|
Feb 8 |
comment |
Replacing values of a function The effect of del /: is to make the definition associate itself with del, which is what you would want. If you omit del /: then it defaults to trying to associate itself with the Head of del[i_, j_]^_ which is Power, which is not what you you would want. Try a_^b_ := f[a,b] to see what happens. |
|
Feb 7 |
comment |
Replacing values of a function When you use the commutator rule two or more times in succession it generates products of Kronecker deltas, so terms such as del[i,j]^2 (etc) can arise. The del /: del[i_, j_]^_ := del[i, j] definition simplifies these. |
|
Feb 7 |
revised |
Replacing values of a function added 831 characters in body |
|
Feb 7 |
answered | Replacing values of a function |
|
Feb 4 |
comment |
Applying TextRecognize on alpha-numerical table I have just checked what happens when you include the whole alphabet by using Join[Range[0,9],CharacterRange["A","Z"],{"+","-","."}]. “B” detects “8” as well as “B”, and similarly “I” detects “1” as well as “I”, but otherwise there are no false alarms or missed detections of alphabetic characters. I haven't checked, but I assume that the false alarm problem can be fixed by forcing the detections to "compete" with each other, as I suggested in my answer. |
|
Jan 31 |
comment |
How to display detailed output in Mathematica Are you asking for a "step-by-step" solution like Wolfram Alpha provides? |
|
Jan 29 |
awarded | Nice Answer |
|
Jan 29 |
revised |
Applying TextRecognize on alpha-numerical table added 189 characters in body |
|
Jan 29 |
revised |
Applying TextRecognize on alpha-numerical table added 226 characters in body |
|
Jan 29 |
answered | Applying TextRecognize on alpha-numerical table |
