http://bit-player.org/2011/chebfun An amateur's outlook on computation and mathematics. Thu, 17 May 2012 10:21:37 +0000 http://wordpress.org/?v=2.6.3 http://bit-player.org/2011/chebfun#comment-3914 Andrew Duncan Tue, 20 Dec 2011 16:05:51 +0000 http://bit-player.org/?p=1060#comment-3914 Sorry I meant: points at which the function is continuous but the first derivative does not exist. Sorry I meant:
points at which the function is continuous but the first derivative does not exist.

]]> http://bit-player.org/2011/chebfun#comment-3913 Andrew Duncan Tue, 20 Dec 2011 16:02:59 +0000 http://bit-player.org/?p=1060#comment-3913 When I was an undergrad we would call points at which the function is continuous but the first derivative is not a "kink". We might have gotten this from Spivak or Rudin's book. I doubt this is standard nomenclature, though. When I was an undergrad we would call points at which the function is continuous but the first derivative is not a “kink”. We might have gotten this from Spivak or Rudin’s book. I doubt this is standard nomenclature, though.

]]> http://bit-player.org/2011/chebfun#comment-3912 brian Tue, 20 Dec 2011 15:13:12 +0000 http://bit-player.org/?p=1060#comment-3912 @Damon McDougall: Thanks. Of course you're quite right. But I now discover a gap in my mathematical vocabulary. If those points are not to be called discontinuities, what <em>do</em> we call them? When we speak of the curve as a whole, we have a nice collection of adjectives for various properties---continuous, smooth, differentiable (and their negations). But how do we describe a point that makes a curve nondifferentiable? Is there some term in common use that I've forgotten or never learned? @Damon McDougall: Thanks. Of course you’re quite right. But I now discover a gap in my mathematical vocabulary. If those points are not to be called discontinuities, what do we call them? When we speak of the curve as a whole, we have a nice collection of adjectives for various properties—continuous, smooth, differentiable (and their negations). But how do we describe a point that makes a curve nondifferentiable? Is there some term in common use that I’ve forgotten or never learned?

]]> http://bit-player.org/2011/chebfun#comment-3910 Damon McDougall Mon, 19 Dec 2011 13:38:51 +0000 http://bit-player.org/?p=1060#comment-3910 Just a brief observation. You mentioned it's necessary to deal with the discontinuities in max(f, hat), but this function is actually continuous. I think you meant to say it's not differentiable. Just a brief observation. You mentioned it’s necessary to deal with the discontinuities in max(f, hat), but this function is actually continuous. I think you meant to say it’s not differentiable.

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