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Symbolics Question

ELSID
4-Participant

Symbolics Question

I do not think this is a bug, so I am posting here.
Is there a way of having Mathcad move the constant to the denominator instead of calculating the value and truncating to the set number of decimal places?
BTW, �T was set to 21 İF
5 REPLIES 5

If you want exact solutions, don't use decimal points in the numbers. The presence of a decimal point forces floating point evaluation by the symbolic processor. But that is generally done with the default 20 digits. I don't know how you got truncation. It also seems that you may have been using the menu (dead) symbolics rather than the usual live symbolics.
__________________
� � � � Tom Gutman

On 11/9/2009 7:30:17 PM, ElSid wrote:
>I do not think this is a bug, so I am posting here.

It isn't. It's a round-off error.

>Is there a way of having Mathcad move the constant to the denominator instead of calculating the value and truncating to the set number of decimal places?

It's a convention that numbers whith decimal dot are "at machine precission" rationals, or "realcons", or other names, depending the language, including for example RPN from Hewlett-Packard.

Actually, it's a short hand for declaring float point values. You can input 1.08 as 108/100 to avoid truncation errors. The reciprocal is true: to input values like 2 as floating point write 2. or 2.0.

Im mcad/maple you can write convert(expr,rational) to have all values as exact ones, and I remember a bug in mcad14 related with truncation and laplace, but searching in the forum seems broken.

Regards. Alvaro.

PD: Time ago I discover that users with a long experience using microsoft word find death symbolics comfortable.

You wouldn't be under stress,
had you left the Mathcad default in place before modifying.

jmG
ELSID
4-Participant
(To:ptc-1368288)

Looks like all 3 are saying the same thing. How would you implement the "usual live symbolics". I got the procedure from one of the e-books ... probably outdated

>>How would you implement the "usual live symbolics".<<

ctl-alt-. symbolic evaluation. That's what should be the major part of the help for symbolic calculation.
__________________
� � � � Tom Gutman
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