19,982 reputation
24193
bio website sites.google.com/a/unca.edu/…
location Asheville, NC
age
visits member for 2 years, 7 months
seen 3 mins ago

I've been a professor of mathematics at The University of North Carolina - Asheville since 1997. I've been using Mathematica since I started graduate school in mathematics at Ohio State in 1989. At that time, we used version 1.1 (as I recall) to teach calculus in our Calculus and Mathematica classes. I've used it pretty much continuously in my teaching and research since then.

In addition to my posts on SE, you can find some of my papers, teaching notebooks and other Mathematica based oddities strewn throughout my website.

In recent years, I've also worked as a part-time consultant to Wolfram Research focusing on development of mathematical content for WolframAlpha.


7h
comment How to Nest a Function with three Arguments?
I suspect he'd like it to work with arguments other than A, B, and dt. Perhaps, a more general pattern would be appropriate?
7h
comment How to prove that all zeros of the complex polynomial $P(z)$ lie in the closed unit disk $|z| \leqslant 1$?
Wrong site - I suspect you want math.stackexchange.com
11h
comment How to find this limit correctly?
I suppose that Assumptions in Limit might simply be applied to simplify the expression ahead of the computation. That would explain the difference in the results and be dismissed as designed. A genuine domain restriction would be more properly dealt with as a third argument.
20h
comment How to find this limit correctly?
@DanielLichtblau That is what I thought. But, then, how do I explain the fact that Limit[n^2 Sin[2*n*Pi], n->Infinity, Assumptions->Element[n, Integers]]==0?
23h
comment How to find this limit correctly?
@belisarius Well, yeah, but that's a discrete plot indicating the limit is $2\pi$ ( I assume, I'm on my iPhone).
1d
comment Importing High Precision (22 digits) data from a file
@jason There is no import as string in my example. I used ImportString since it works exactly as Import but allows one to show a whole example without reference to an internal file. If you want that specific number, then that specific number will need one more zero in your input file. Keep in mind also that you should get the binary number with the specified precision closest to your input, so that trailing digits are often present. I can't verify your 8.24574098106 as I get 8.24574097909*^8, which seems quite right.
1d
comment Use Mathematica to calculate the area enclosed between two curves
Is there an obfuscated Mathematica contest?? :)
2d
comment Specifying Range of RSolve
@QuinnCulver I mean that $|x_{n}-3/4|<(|x_{n-1}-(3/4)|)/2$. In words, the distance between $x_n$ and $3/4$ is a little less than half the distance between $x_{n-1}$ and $3/4$. You can verify this numerically by looking at Ratios[N[Table[q[n],{n,0,9}]-3/4]] - you'll see a sequence converging to $1/2$. Analytically, you're iterating $f(x)=(-2x+3\sqrt{4x+1}-3)/2$ which has a fixed point at $x=3/4$ satisfying $f'(3/4)=1/2$.
2d
comment Approximate the largest and the smallest values of the integral
@ubpdqn I think your answer is perfectly appropriate! By math.se, I meant math.stackexchange.com.
2d
comment Approximate the largest and the smallest values of the integral
The integrand is positive on the interval $1\leq x \leq 3$ so the extremes certainly happen at the endpoints. Though, perhaps you mean to ask this on math.se?
Aug
28
comment Exporting as GIF
No problem - I'm glad you figured it out.
Aug
19
comment Coordinate extraction and manipulating graphs as graphics objects
Oh, it's just one tiny little change. I thought about editing your answer but you can do it, if you want. And, yes, I've posted the GraphConvert thing before but more recently learned of the more intuitive approach with Show.
Aug
19
comment Coordinate extraction and manipulating graphs as graphics objects
The GraphComputation`GraphConvertToGraphics function is called by Show when applied to a Graph. Thus, Show[g] accomplishes the same thing.
Aug
16
comment What's new in Mathematica 10 that begginers must know?
JuliaSetPlot is my personal vote - but it certainly depends upon your interests.
Aug
11
comment DSolve problem with system of linear ODEs
I have to admit that I find it an odd syntactical difference that NDSolve works while DSolve does not. I don't think I'd call it a bug, though.
Aug
11
comment DSolve problem with system of linear ODEs
You need to define X: X[t_] = {x[t], y[t], z[t]}.
Aug
11
comment Automatically detect largest interval over which NDSolve can find a solution
@MichaelE2 You are probably right - I was clearly being paranoid. :)
Aug
11
comment Fill gap created by Exclusions
I feel strangely compelled to upvote this!
Aug
10
comment Fill gap created by Exclusions
You're plotting two different functions and each has a reasonable choice of Exclusions independent of the other. Why don't you use to Plot command and combine the results with Show? You might also try the TrackedSymbols -> {t0,s} in your Manipulate command. Finally, with 9 questions now asked, I think it would be reasonable for you to properly format your code - it's just a matter of indenting your code block four spaces.
Aug
10
comment Plotting a parametric function with three input variables
@hieron The With statement is certainly not necessary but makes it super simple to extract individual plots. You can use With[{c=Pi/2},___], for example to look at that particular image. It arose because I did exactly that when trying to figure out what was going on mathematically. Clearly, this would be particularly nice, if there were more cs in the expression.