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Re: Low precision exponentiation
Posted:
Feb 18, 2013 6:00 AM


The problem is that you entered 2.5 as a machine precision number, so you are only going to get machine precision output. The way to get high precision output is to start with the exact 5/2 instead of the machine precision 2.5.
N[(5/2)^125, 50]
In general, you should enter numbers into Mathematica exactly whenever possible. Enter rational numbers as fractions, and don't use decimal approximations for numbers like Pi or Sqrt[3]. Just put them in exactly, and then you can use N[] to get the output to whatever precision you want.
Helen Read University of Vermont
On 2/17/2013 4:08 AM, Blaise F Egan wrote: > I am trying to evaluate 2.5^125 to high precision. > > R gives 5.527147875260445183346e+49 as the answer but Mathematica > with N[2.5^125,30] gives 5.52715*10^49 and says that is to machine precision.> > I am inexperienced at Mathematica. Am I doing something silly? > > Blaise >



