Newbie
Posted 20 April 2015 - 10:07 PM
I have a Casio fx-CG10 and have never been able to change a decimal to a fraction. The F->D works for fraction to decimal but not for decimal to fraction. I've also tried the a b/c button but that also doesn't work. Is there some setting that I can change to make this work?
Example problem= ∫(upper=1, lower=0) (x^1/2 -x^3)dx= 4.166666667
Casio Freak
Posted 21 April 2015 - 08:39 AM
You need any CAS calculator.
According the UG the computing with sqrt has some limitation, page 2-4 and 2-5.
Some models, like fx-991DE PLUS and fx-991DE X, have function for converting repeating decimal to fraction. It is strange the Prizm is without this function.
Newbie
Posted 01 May 2015 - 02:41 AM
The prizm can readily convert a decimal to a fraction and back again, as long as it was computed internally as a fraction in the first place. The F->D button acts as a toggle, it goes both ways. The example sited at the top creates a result internally by means of an iterative method that will not produce results expressable as a fraction, as was correctly said, a CAS calculator would be needed.
On my Prizm and my TI-89 (in approximate mode) I get .41667 as an answer.
On my TI-89 in exact mode, using the CAS features, it comes out as the fraction 5/12.
Newbie
Posted 01 May 2015 - 03:16 AM
You can convert your Prizm into a CAS calculator, with a few limitations, by installing the Eigenmath application.
You can find this software here: http://gbl08ma.com/c...prizm-software/
Using this package, I entered ' integral (x^(1/2) - x^3, x) '
Eigenmath returned: (2/3)x^(3/2) - (1/4)x^4
Since the upper bound is x=1, substituting, you get simply (2/3) - (1/4) which the Prizm, either in Eigenmath or using it's native software, will give you 5/12, the correct answer. the lower bound of x=0, should be subtracted from this of course, but since it nets to zero, doesn't change the answer.
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