when is y=x+a not a straight line?

*To*: mathgroup at smc.vnet.net*Subject*: [mg129005] when is y=x+a not a straight line?*From*: Richard Fateman <fateman at cs.berkeley.edu>*Date*: Sat, 8 Dec 2012 01:28:56 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net

Try this a=0``-0.5 ListPlot[Table[{x, a + x}, {x, -10, 10}], Joined -> {True}] This is probably not a surprise to some people. If you think the value for "a" could never happen, try this: a=N[1,20] Do[a=2*a-a,{43}] Compare to Plot[x+a,{x,-1,10}] which shows that Plot evaluates its first argument in an manner inconsistent with Table's method. Cheers. RJF