Re: Displaying decimals
- To: mathgroup at smc.vnet.net
- Subject: [mg63495] Re: [mg63476] Displaying decimals
- From: "David Park" <djmp at earthlink.net>
- Date: Tue, 3 Jan 2006 01:24:57 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
Lea,
The primary purpose of N is to convert EXACT numbers, such as Pi or 1/3, to
approximate (decimal) numbers. So if N is given an approximate number to
begin with it does nothing. (However, the behavior of N has varied some over
versions.) If an approximate number has a precision less than or equal to
$MachinePrecision (usually about 16 places) then it is always displayed with
6 places. (This can be changed in the Option Inspector). Your numbers are,
just barely, within $MachinePrecision. So they display with 6 places and N
does nothing to change that.
The following illustrates the effect of N on a machine precision number and
on an exact number.
N[3.3333333333333333, 20]
3.33333
N[Pi, 20]
3.1415926535897932385
In any case, the solution is simple. Use NumberForm instead of N.
NumberForm[slope[50], 20]
163.189230604459
If you want to show zeros on the right...
NumberForm[slope[50], {20, 17}, NumberPadding -> {"", "0"}]
163.18923060445900000
Look up NumberForm in Help and you will see many options to control the
display of numbers.
David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/
From: Lea Rebanks [mailto:lrebanks at netvigator.com]
To: mathgroup at smc.vnet.net
Given the enclosed function, I can not make Mathematica v5.1 display
greater than 3 decimals. Please help.
slope[x_]:=160.245051009838+0.05888359189242*x
EG. slope[50] = 163.189
I don't know how or why this is happening. I have tried N[expr,20] to
no avail.
Many thanks for your attention.
Lea Rebanks.