machine precision number plot fixed in V6?

*To*: mathgroup at smc.vnet.net*Subject*: [mg83064] machine precision number plot fixed in V6?*From*: congruentialuminaire at yahoo.com*Date*: Fri, 9 Nov 2007 05:14:52 -0500 (EST)

Hello Mathematica UG: I was doing some work with the PrecisionPlot package (http:// library.wolfram.com/infocenter/MathSource/715/) When I ran it under V6, no output was emitted. So I looked again at the documentation provided by Ted Ersek. Even though it is 8 years old, it contains the following function and plot which does not work correctly as recently as V5. In V6, the invocation with SetPrecision works and emits a smooth plot (presumably eliminating the need for this package). Here are the lines of code. ----------------------------------------------------------- (* a function that does not plot well with machine-precision numbers *) f2[x_] = ArcSec[x] - Normal[Series[TrigToExp[ArcSec[x]], {x, \ [Infinity], 7}]] (* a jagged plot results under V5 and V6 *) Plot[f2[t], {t, 25, 40}] (* a smooth plot results only under V6 *) Plot[f2[SetPrecision[t, 17]], {t, 25, 40}] ------------------------------------------------------------ If there is a simple explanation for what was fixed in V6 to make this work, I am interested to know. TIA. Regards..Roger