18,779 reputation
41963
bio website none
location Ann Arbor, MI
age 76
visits member for 1 year, 10 months
seen 3 hours ago

I am a retired software developer. I retired at the end of 2003 and since then my computer programming activities have been for recreational purposes. I find Mathematica excellent for that.

I started using Mathematica in 1997 (Ver. 3). I am currently using Ver. 9. Although I have used Mathematica for all kinds of stuff, I use it mostly to pursue my long standing interest in Euclidean geometry, both in the classical Greek synthetic form and in the more modern analytical form.


Aug
27
revised Specifying initial conditions for a PDE
Improved formatting
Aug
27
revised Tuples without self-loop
Minor clean-up
Aug
27
revised Export MatrixPlot graphics to PDF
deleted 5 characters in body; edited title
Aug
27
revised NDSolveValue producing message: Input is not an ordinary differential equation
Middling clean-up
Aug
27
revised Power::infy: error using FindFit
Middling clean-up
Aug
27
revised What is the meaning of a result of {{}}?
deleted 28 characters in body; edited tags; edited title
Aug
27
revised How to solve three equations with four unknowns iteratively?
Improved formatting
Aug
27
revised Extract the minimum positive root from a quintic
Middling clean-up
Aug
27
comment Dual core CPU — Mathematica uses only 29% of one core
This question appears to be off-topic because it is not really about Mathematica or any of the other Wolfram Research software for which questions are accepted on this site.
Aug
27
comment How to do DateDifference on table items containing dates
@Elisa. I am using V10. Earlier versions of Mathematica didn't require QuantityMagnitude to get a numeric result.
Aug
26
revised How to do DateDifference on table items containing dates
edited tags; edited title
Aug
26
answered How to do DateDifference on table items containing dates
Aug
26
awarded  Nice Question
Aug
26
comment Can I check if an expression is positive using assumptions?
To set global assumptions, use $Assumptions = {{c1, c2, λ, μ} > 0, Element[{c1, c2, λ, μ}, Reals], μ > λ}.
Aug
26
revised Can I check if an expression is positive using assumptions?
Improved formatting
Aug
26
reviewed No Action Needed Can I check if an expression is positive using assumptions?
Aug
26
revised How to make Epilog render behind the main plot
deleted 11 characters in body; edited title
Aug
26
comment How to make Epilog render behind the main plot
Use Prolog, not Epilog.
Aug
26
revised Dual core CPU — Mathematica uses only 29% of one core
deleted 88 characters in body; edited title; edited tags
Aug
25
comment Counting the zeros in a factorial expansion
Let us note for the record that Count[IntegerDigits[1000!], 0] gives the result 472, essentially instantaneously.