# DeepYellow

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bio website location age 49 member for 1 year, 9 months seen Jan 18 at 12:53 profile views 15

I'm a professional programmer with a mathematical disposition.

 Nov1 comment Name this concept: Comparing equal sized vectors vs. comparing featuresYou might want to ask this on astronomy.stackexchange.com. I think they do something similar to align sequences of images in order to get an enhanced composite image. Sep29 comment circle that touch quadrantal internally@J.M.: I'm assuming kim want's the inscribed circle Sep26 comment Why is this curve convex?Are you sure they want you to use polar coordinates? You could put $\theta$ on the x axis and r on the y axis. Sep21 comment 4 items add up to and multiply to 7.11 what are the value of the items?@anon: Right you are! (duh!) Sep21 comment 4 items add up to and multiply to 7.11 what are the value of the items?@anon: if $\pi$ is too expensive, maybe I can just buy a piece? Sep21 comment 4 items add up to and multiply to 7.11 what are the value of the items?Hmmm, the prime factors of 711 are 3*3*79. There aren't many choices for the prices here, and none of them add up to 711. For example, 1*1*9*79 = 711, but the sum isn't even close. Sep21 comment 4 items add up to and multiply to 7.11 what are the value of the items?Hint: This is a Diophantine problem. Besides the sum and product, you also have that the answers (expressed in cents) are integers. Sep21 comment Curvature of the image of a curve projected onto a surfaceI haven't tried yet, but will sometime in the next week (or two). I don't see why it wouldn't though. I'll post the Mathematica results here when I do. Sep20 comment Curvature of the image of a curve projected onto a surfaceThanks, I appreciate the effort you put into this. I really like the idea of creating an orthogonal basis in the tangent space. I can make this work. Sep20 comment Curvature of the image of a curve projected onto a surfaceThanks for this. I'm not clear why you say that I forgot to mention p, k, and d, (as k and d are of your own construction) and I don't know what you mean "it's a pullback". I'm not I can I turn this into a finished solution for d given that S is unknown in advance (we are only guaranteed that we can inquire it's derivatives). Sep20 comment Curvature of the image of a curve projected onto a surfaceIt's not clear to me that the construction as you describe it gives the correct curve. Can you justify the idea that there is a locally aligned parametrization that has the second derivative projection properties? Unfortunately I have to award the bounty soon, so please answer quickly. I'll give it some further thought myself. Sep18 comment Curvature of the image of a curve projected onto a surface@alex: the surface will generally be a NURBS surface, so there is no hope of an implicit form. Thanks for the suggestion. Aug31 comment “Mathematical Induction”ODEs do it for me every time! Aug25 comment Curvature of the image of a curve projected onto a surface@anon: Thanks for this. I intend to see if I can get it to work in Mathematica, but I haven't gotten to it yet. Aug18 comment Curvature of the image of a curve projected onto a surfaceI modified the question to avoid references to derivatives in $C_S$. Aug18 comment Curvature of the image of a curve projected onto a surface@Jesse: Hmmm, that didn't come out very nice, did it. I guess you can't use html in comments? How did you get your subscripts? Aug18 comment Curvature of the image of a curve projected onto a surface@Jesse: Actually I was a bit sloppy on my wording. CS'(t0) is proportional to CS'(t0), which is all I need in my case. This problem comes from my desire to walk along the surface tracing out the projection from an initial point. I intend to do this by estimating a step with derivative information, and then correcting by iteration. The approach of walking along the curve projecting points is flawed because the projection is one-to-many.