Re: more plotting peculiarities

*To*: mathgroup at smc.vnet.net*Subject*: [mg124106] Re: [mg124075] more plotting peculiarities*From*: Richard Fateman <fateman at eecs.berkeley.edu>*Date*: Mon, 9 Jan 2012 03:17:30 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <201201080922.EAA01272@smc.vnet.net> <4F09EDC6.8020206@math.umass.edu>

On 1/8/2012 11:25 AM, Murray Eisenberg wrote: > Those results are wholly unsurprising (Version 8). After all, look at > some sampled values in the domains, e.g.: > > 1.0 + 2.0^-47 Range[-5, 5, .1] // NumberForm[#, 15] & > 1.02 + 2.0^-47 Range[-5, 5, .1] // NumberForm[#, 15] & > > And then take Cos of each list. OK, then explain why 1.0 vs 1.02 makes a huge difference. Do you not find that surprising? > > Actually, the plot from the first expression does NOT look empty to > me: I see a thickened horizontal axis located at height y = 0.54. Yes, I saw that too. The plot looks empty, though. It certainly is highly uninformative. > Using option AxesOrigin -> {0,0} reveals what appears to be a line at > that height. > > And the plot from the second is essentially a linearization, given > that its range is from around 0.523365951251619 to 0.52336595125168. Yes, actually what I expect from a normal plotting program is steps that illustrate the discretization of the function values to particular machine floating point numbers. How do you suggest doing that with Mathematica? > > On 1/8/12 4:22 AM, Richard Fateman wrote: >> Plot[Cos[1.0 + n*2.0^-47], {n, -5, 5}] looks empty >> >> Plot[Cos[1.02 + n*2.0^-47], {n, -5, 5}] >> looks like a straight line with slope about -1 >> >> version 7 >> >

**References**:**more plotting peculiarities***From:*Richard Fateman <fateman@cs.berkeley.edu>