Two things about the working of CAS

Antoni Gomà shared this problem 8 years ago
Answered

One of the topics that I will coment below refers to the x = icon for solving equations and the other topic is what happens whit File -> New and objects defined in CAS.

Possible bugs?


First topic: It is possible that in the version 4.2.13.0 WebStart (28 december) the icon x = not work to solve an equation of first degree? (but it works correctly for solving systems of equations) (!)

(Photo CAS1.jpg)


Second topic: It seems to me that when we have objects defined in the CAS and we do File -> New, these objects (or "some of these objects") are still not been removed.

File-->New is working well?

Should not happen that with the action File -> New all items "disappear from memory?"

(Photo CAS2.jpg)0d3d6b9c981fae4be14dbb844905711b

68ebd20c97a98c1b1deb9cfd1f017c4e

Comments (10)

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1

Sorry, I can't see either problem here.


Please state exactly what you typed and clicked on.

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File - New should prompt you to save if you haven't done so, then close the old file and open a new one. The old is the same as it was (if you save), end the new one is empty (or should be - I have no problem with this).


Typing 4x + 8 and then clicking the Solve button works fine. However, if I type a := 4x + 8 and then click the button without first hitting Enter, the application freezes up totally and has to be force closed.


Using 4.2.13 on W7, latest Java update.

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Sorry, I can't see either problem here.

Please state exactly what you typed and clicked on.


It seems to me (with Windows XP, GeoGebra version 4.2.13.0, Java 1.7.0_10) taht GeoGebra do not works fine as say themadmathematician.


To me happens exactly the same if I work with the WebStart version or with appletstart version.


Then I will state what I type.

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About the [size=150]x =[/size] icon

I type 4x + 5 = 7x -3 (equation of one variable) at the Row 1 of CAS.

I select row 1

I click icon x = for solve

I get the message Please check the structure of your selection


If, like suggest themadmathematician, I type 4x+5 (instead of one equation) I get the same response


However, if in row 1 I write 3x+4y=7, in row 2 I write 5x-2y=7 , select rows 1 and 2, and clik the x= icon... this works fine.

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About the File --> New


After working in CAS, and feninig some objects with :=

I select File --> New

To the question Do you want save the changes? I click Don't save

The new file is not empty!

The objects defined early, in the "not saved file", yet exist!

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The images attached to my previous post illustrate why I said.

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OK, strange - Can you try to post the two files - old and new - so that murkle can have a look at them when he comes back. Also try to give some information about your system, operating system, java version etc.

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Thanks, I can reproduce the first problem: http://jira.geogebra.org/br...


I still need more detail about exactly what to type to get the second one if possible.

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Thanks, I can reproduce the first problem: http://jira.geogebra.org/br...


I still need more detail about exactly what to type to get the second one if possible.


I type in row 1 of CAS

A:=(x+3)^2-5 (x+5)^3

I can see like answer -5 x³ - 74x² - 369x - 616


I click to File --> New


In the new file I type in row 1 of CAS A

I get -5 x³ - 74x² - 369x - 616


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That is, some objects remain "alive" after we have done File -> New

They are not "all objects" but some (yes: number or expressions defined with Name:= ...., points --in this case even if the name is created by GeoGebra when we do show the object in graphics zone-- ... not: lnes shown at graphisc window, functions,...))

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(1) fixed in 4.2.15.0


Sorry, still can't replicate (2) - anyone else manage?

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Ad 2): version 4.2 keeps values of CAS variables in two places which may result in this bug, 4.9.90+ has them in one place. So we just need to test 4.9.* enough to be able to backport these changes safely.

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Murkle,... I've seen that has been fixed in version 4.15 the correct working of icon x = to solve equations. Thanks!


Kondr,... with your comment I can see the answer to something that I wanted to ask:

Is'n it that the version of CAS built into GeoGebra 4.2 is not the same as CAs of GeoGebra Beta Release 5? (two versions of 11 January).

There are certain aspects of automatic recalculation that seems to me that not work fine in CAS of 5.0.

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Hi,


yes, CAS in 5.0 is unstable right now and should be only used for testing.

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