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Re: Rounding?


On 1 Oct 2005, at 15:55, Tom De Vries wrote:

> Hello everyone,
>
> Sorry if this is an obvious question.  I'm wondering why the two  
> results
> below are different?
>
> I'm creating programs to generate test questions, and I need to  
> know that my
> computer generated answers will match the student answers, to say,  
> three
> decimal places.  So the answer is -0.0625  "exactly", the first  
> result makes
> sense to me, the second doesn't.
>
> If there is a reason for this, is there are way to insure I can  
> make the
> first result look like the second result all the time??
>
>
> SetAccuracy[-0.0625,4]
>
> -0.063
>
> ToString[SetAccuracy[-0.0625,4]]
>
> -0.062
>
>
> Thanks for your input!
>
>
> Tom De Vries
>
>


This is because ToString by default uses the OutputForm of your  
expression:


OutputForm[SetAccuracy[-0.0625,4]]

-0.062

Compare this with:


ToString[SetAccuracy[-0.0625,4],TraditionalForm]


-0.063

and


ToString[SetAccuracy[-0.0625,4],InputForm]


-0.0625`2.7958800173440745


Andrzej Kozlowski


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