Two IF-sentences doesn’t work in CAS-view

Aritmometer shared this problem 2 months ago
Not a Problem

I wondered why I couldn’t get a IF-sentence to work in CAS-view, and found out that the following simple IF-sentence combinations doesn’t work in CAS-view.


1.

c = “+”

T = “(a + b)”

$1 = a

$2 = T

$3 = If[ IsEqual[ c, “+” ] == true, $1 * $2, If[ IsEqual[ c, “-“ ] == true, $2 - $1 ] ]

This input can’t be used.

But this work:

$3 = $1 * $2

$3 = $2 - $1


2.

d = “a”

c = “+”

T = “(a + b)”

$1 = T

$2 = If[ IsEqual[ c, “+” ] == true, d * $1, If[ IsEqual[ c, “-“ ] == true, $1 - d ] ]

This input can’t be used.

But this work:

$2 = d * $1

$2 = $1 - d


I need to use those kinds of IF-sentences in CAS-view when the students use a dropdown-menu to choose the kind of operation they would like to use to isolate a letter in a formula and also get a description shown in text that describes what have been done and to get the formulas written in a table where they are aligned by their equal sign.

Comments (4)

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1) please always post your .ggb file

2) IsEqual() isn't a CAS command so there's no point using it there instead of the Algebra View - you can use == instead

3) There's no point using the CAS for checking Strings anyway, just make sure it has a label and you can do

c=="+"
or (more robust)

c+"" == "+"

in the Algebra View

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Yes, I tried your suggestions first. But it didn’t work in CAS-view as long as one of the sides was a text-string with “” around it.

I then found out that if I used the command IsEqual[] in CAS-view, then it worked with the text-string with “” around it.

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The IF-sentence was placed in CAS-view from a click-script.

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I have been doing some tests

/h97XHlO5755IwAAAABJRU5ErkJggg==

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