Mail Archives: djgpp/1997/12/14/19:33:06

From: "A. Sinan Unur" <sinan DOT unur AT cornell DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Dual monitors with rhide?
Date: Sun, 14 Dec 1997 16:23:35 -0500
Organization: Cornell University (
Lines: 34
Sender: asu1 AT cornell DOT edu (Verified)
Message-ID: <>
References: <19971214071301 DOT CAA28133 AT ladder02 DOT news DOT aol DOT com> <670a5n$ibe AT freenet-news DOT carleton DOT ca> <3493DBDF DOT BA86224 AT cornell DOT edu> <349442D2 DOT 71F0 AT indiana DOT edu>
Mime-Version: 1.0
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

Benjamin F. Keil wrote:
> A. Sinan Unur wrote:
> >
> > Paul Derbyshire wrote:
> > <SNIP>
> > > you're in deep doodoo), or a certain editor-cum-operating-system I
> > > shall not name, which has a learning curve like e^x and a manual 
> > > the size of a phone book and half as well organized ;-)
> >
> > that is supported by neither theory nor fact. it is not supported by
> > fact, because people do learn it. a learning curve such as e^x means
> > there will never be any learning. theoretically, for the concept of
> > 'learning curve' to have any meaning, the function should probably 
> > be strictly increasing and concave.
> e^x fits that description.  e^x is everywhere increasing and has 
> upwards concavity.

i know this is off-topic, but i hate seeing my supposedly humorous
responses ruined this way ;-) send flames by e-mail please.

a twice differentiable function is said to be (strictly) concave if its
second derivative is (negative) nonpositive, and (strictly) convex
(which is what you are calling 'upwards concavity') if its second
derivative is (positive) nonnegative.
A. Sinan Unur
Department of Policy Analysis and Management, College of Human Ecology,
Cornell University, Ithaca, NY 14853, USA

mailto:sinan DOT unur AT cornell DOT edu

- Raw text -

  webmaster     delorie software   privacy  
  Copyright 2019   by DJ Delorie     Updated Jul 2019