# Jonas Teuwen

Delft, The Netherlands

fa.its.tudelft.nl/~teuwen

Age: 29

I'm a PhD candidate in analysis (harmonic analysis). I have a Master of Science degree in mathematics (analysis). My email address is jonasteuwen@gmail.com. And my [Google Scholar profile](http://scholar.google.com/citations?user=Jz3tRZMAAAAJ). (I agree, not much there yet. Should change soon!) I would appreciate it if you would correct my spelling and grammatical errors.

 Jul 2 awarded Enlightened Jul 2 awarded Nice Answer Jun 20 awarded Popular Question Jun 12 awarded Good Question Jun 11 awarded Popular Question May 22 awarded Popular Question May 19 awarded Nice Question Apr 11 awarded Popular Question Mar 19 awarded Nice Question Jan 4 awarded Popular Question Nov 16 awarded Yearling Nov 16 awarded Yearling Nov 3 awarded Nice Question Oct 9 comment Coloring random points in an annulus@kguler: Yes, when I set ```randomInAnnulus[R1_, R2_, cb_: 0, n_: 100] := Transpose@{# Cos@#2 + cb, # Sin@#2 + cb} &[ Sqrt@RandomReal[{R1, R2}^2, n], RandomReal[2 \[Pi], n]];``` and I pick cb so large that x*y > 0 for all points I get an error. Oct 8 comment Coloring random points in an annulusIt does work well, but if I replace the condition for the check with another one it fails if there are no such points (for instance when I shift the annulus in the first kwadrant. Is there an easy way to resolve this? Oct 7 accepted Coloring random points in an annulus Oct 6 comment Coloring random points in an annulusIs there any advantage (i.e., speed) in using any of those three? Oct 6 comment Coloring random points in an annulusYes, I have noticed it is quite slow. Do you have any ideas how to do it faster? Oct 6 asked Coloring random points in an annulus Sep 30 awarded Explainer