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RE: First time user - Exact and approximate numbers

  • To: mathgroup at smc.vnet.net
  • Subject: [mg43634] RE: [mg43631] First time user - Exact and approximate numbers
  • From: "David Park" <djmp at earthlink.net>
  • Date: Sat, 27 Sep 2003 04:57:54 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Jim,

The 0.5 is the culprit. As soon as you introduce even one approximate number
(a number with a decimal point) into your expression, the entire expression
is changed to approximate numbers. Then your whole expression is evaluated
to a single approximate number.

Do the following.

(111 + 4*Sqrt[770])^2
%//Expand
							giving
(111 + 4*Sqrt[770])^2
24641 + 888*Sqrt[770]

Without any approximate numbers, Mathematica now keeps Sqrt[770] as an exact
number and does not combine it with integers.

You can enter Sqrt numbers by using the button on the InputPalette. Or you
can use Ctrl 2 770 Ctrl space. Or you could have used your initial form but
entered (1/2) instead of .5.

David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/


From: Jim Dars [mailto:jim-dars at comcast.net]
To: mathgroup at smc.vnet.net

Hi All,

I input

(111+4*(770)^.5)^2

and I wish to have mathematica reply

(24641 + 888*(770)^.5)

How do I achieve this?  Presently I'm getting

(111+4*(770)^.5)^2

Best wishes, Jim


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