Re: more plotting peculiarities

*To*: mathgroup at smc.vnet.net*Subject*: [mg124105] Re: more plotting peculiarities*From*: Chris Young <cy56 at comcast.net>*Date*: Mon, 9 Jan 2012 03:17:09 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <jebnc5$18u$1@smc.vnet.net>

On 2012-01-08 09:24:21 +0000, Richard Fateman said: > 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 This is due to what I think are some deceptive plotting defaults in Mathematica. Where the axes cross is not necessarily the origin; not in this case, at any rate. I think it would be a lot clearer if the x-axis in this case were either plotted in dashed form or grayed out a little bit more, to show its not at its expected position, y = 0. If you specify that the axes must cross at the origin, you'll see that in both cases the slope was tiny, nowhere near what it looked like: Plot[Cos[1. + n/2.^47], {n, -5, 5}, PlotStyle -> {Red, Thick}, AxesStyle -> Lighter[Blue, 0.7], AxesOrigin -> {0, 0} ] Plot[ Cos[1.02 + n/2.^47], {n, -5, 5}, PlotStyle -> {Red, Thick}, AxesStyle -> Lighter[Blue, 0.7], AxesOrigin -> {0, 0} ]